Protein-containing emulsions and adhesives, and manufacture and use thereof

ABSTRACT

This invention provides emulsions and adhesives comprising proteins that can be isolated from a variety of sources including renewable plant biomass, and methods of making and using such emulsions and adhesives.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/067,238, filed Mar. 11, 2016, which is a continuation of U.S. patentapplication Ser. No. 13/951,710, filed Jul. 26, 2013, now U.S. Pat. No.9,309,444, which is a continuation of U.S. patent application Ser. No.12/719,521, filed Mar. 8, 2010, now U.S. Pat. No. 8,519,031, whichclaims the benefit of and priority to U.S. Provisional PatentApplication No. 61/246,208, filed Sep. 28, 2009, and U.S. ProvisionalPatent Application No. 61/157,944, filed Mar. 6, 2009; the entirecontents of each of which are hereby incorporated by reference herein intheir entirety.

FIELD OF THE INVENTION

The invention relates to isolated proteins, emulsions and adhesivescontaining such proteins, and to methods of making and using suchproteins, emulsions and adhesives.

BACKGROUND

The use of organic polyisocyanate, epoxy, urea formaldehyde (UF), andphenol formaldehyde resole resins (PF resins), and various combinationsof these adhesives is well known for the production of consolidated woodcomposites such as chipboard, fiberboard, and related composite woodproducts as well as in making engineered lumber composites. The cure ofthese resins often is accelerated in these end-use applications by usingheated presses with press temperatures exceeding 100° C., and often 200°C. In some specialized structural (or engineered) lumber applications itis often impractical to use heat to drive the cure of the adhesivebecause the engineered wood composite structures are too large foradequate heat transfer. In these structural applications, adhesives thatcure at ambient temperatures are preferable. The challenge informulating all of these resins is to achieve an adequate balancebetween the need for rapid cure at elevated or near-ambienttemperatures, and to maintain a suitably long working time (or potlife).

Moreover, recent environmental concerns recognized the need forreplacing UF and PF resins with more environmentally friendly resinsthat have the bond strength obtained with the UF resins, whileeliminating formaldehyde and providing similar or better moistureresistance for the final product. Although polyisocyanates, for example,PMDI, are capable of providing these characteristics, to-date, manyattempts to commercially use PMDI in replacing UF have failed due tocost and processing concerns.

There is still a need in the wood products industry for highperformance, lower cost and environmentally cleaner adhesives thatperform as well as polyisocyanates. Various attempts have been made toblend polyisocyanate adhesives with other kinds of adhesives but nonehave had significant commercial success in the certain industries, forexample, the commodity wood products industry. The use ofisocyanate-functional prepolymers has been extensively studied.Unfortunately, in many cases, the prepolymers simply dilute theperformance of the isocyanate. It is, therefore, desirable to have amodifying agent or prepolymerizable species that can be combined with apolyisocyanate or another similar resin in order to reduce the cost ofthe latter by reducing the amount of polyisocyanate, which is neededwithout reducing performance such as bond strength and moistureresistance.

SUMMARY OF THE INVENTION

The invention provides emulsions and adhesives, for example,thermosetting adhesives, that contain a polypeptide fraction that can beisolated from variety of starting materials, including renewable plantbiomass. An important component that provides the emulsions andadhesives with their advantages is the isolated polypeptide composition.The plant biomass generally is a waste by-product of the agriculturalindustry and, therefore, the invention provides commercially usefulemulsions and adhesives that are environmentally friendly.

Certain of the isolated polypeptide fractions described herein can beuse to disperse or emulsify an oil-in-water or water-in-oil. As aresult, the polypeptide fractions can be used to disperse oils commonlyused in the manufacture of adhesives. Depending upon the formulationchosen, the resulting adhesives perform as well or better thanconventional, commercially available high performance adhesives. Inaddition, the invention provides both one-part adhesives (a singlemixture that, without the addition of other components, functions as anadhesive) or two- or multi-part adhesives (adhesives created by mixingtogether two or more parts, which when mixed together function as anadhesive). In addition, the polypeptides can be used to disperse oremulsify oils during the clean up of oil spills or during tertiary oilrecovery. Certain of the isolated polypeptide fractions described hereincomprise water-soluble proteins, which can be used to producewater-soluble adhesives. The resulting water-soluble adhesives can beused, for example, to stick paper onto glass. The water-soluble proteincan also be cross-linked using conventional cross-linking agents toproduce water-resistant adhesives.

In one aspect, the invention provides an adhesive compositioncomprising: (a) from about 5% to about 90% (w/w) of a reactiveprepolymer; and (b) from about 10% to about 99% (w/w) of an isolatedpolypeptide composition capable of dispersing the reactive prepolymer inan aqueous medium, for example, water or a water-based solution. Thewater-based solution can contain a plurality of dissolved componentsand/or can contain a dispersed or emulsified latex polymer.

In certain circumstances, the reactive prepolymer is apolyisocyanate-based prepolymer, an epoxy-based prepolymer, a latexprepolymer, or is a combination thereof. Depending upon the componentsof the adhesive, the prepolymer and isolated polypeptide composition canbe mixed and stored as a mixture until use (for example, when anactivator or catalyst is added to the mixture, or where the mixture isstored under conditions so that curing does not occur). Alternatively,when no other additives are needed to initiate a reaction between thereactive prepolymer and the isolated polypeptide composition, thereactive prepolymer and the polypeptide composition are mixedimmediately prior to use.

In another aspect, the invention provides a two-part adhesivecomposition comprising: (a) a first part (Part A) comprising from about5% to about 90% (w/w) of a reactive prepolymer, wherein the reactiveprepolymer is a polyisocyanate-based prepolymer, an epoxy-basedprepolymer, or a combination thereof and (b) a second part (Part B)comprising from about 10% to about 99% (w/w) of an isolated polypeptidecomposition capable of dispersing the reactive prepolymer in an aqueousmedium.

Depending upon the composition of Part A and Part B, Parts A and B aremixed immediately prior to use. In one embodiment, the adhesive, whencured, comprises from about 1% to about 95% (w/w) of non-volatilemoieties of Part A and from about 5% to about 99% (w/w) of non-volatilemoieties of Part B. Furthermore, depending upon the application andfunctionality of the adhesive composition, the weight ratio of solids inPart B to the prepolymer can be in the range of from 100:0.1 to 0.1:100.

In each of the foregoing aspects, the polyisocyanate-based prepolymercan be an organic polyisocyanate; or a reaction product between anorganic polyisocyanate and, for example, a polypeptide, a polyol, anamine based polyol, an amine containing compound, a hydroxy containingcompound, or a combination thereof. Furthermore, in each of theforegoing aspects, the adhesive composition can further comprise acatalyst.

The epoxy-based prepolymer can be an epoxide containing compound.Alternatively, the epoxy-based prepolymer can be a reaction productbetween an epoxy and, for example, a polypeptide, a polyol, an aminebased polyol, an amine containing compound, a hydroxy containingcompound, or a combination thereof. The epoxy can be selected from thegroup consisting of a diglycidyl ether of bisphenol-A, a diglycidylether of bisphenol-A alkoxylate, an epoxy novolac resin, expoxidized soyoil, epoxidized linseed oil, epichlorohydrin, a glycidyl ether-typeepoxy resin derived from a polyphenol by reaction with epichlorohydrin,and a combination thereof.

In another aspect, the invention provides an adhesive compositioncomprising: (a) from about 5% to about 90% (w/w) of a reactiveprepolymer selected from the group consisting of an organicpolyisocyanate, a reaction product between an organic polyisocyanate anda polypeptide, a polyol, an amine based polyol, an amine containingcompound, a hydroxy containing compound, or a combination thereof; (b)from about 10% to about 99% (w/w) of an isolated polypeptide compositioncapable of dispersing the reactive prepolymer in an aqueous medium; and(c) an optional catalyst.

In each of the foregoing aspects of the invention, the isolatedpolypeptide composition is capable of dispersing the reactive prepolymerin the aqueous medium to produce a stable dispersion or a stableemulsion. The dispersion or emulsion exhibits substantially no phaseseparation by visual inspection for at least 5 minutes after mixing thepolypeptide composition with the reactive prepolymer. In certainembodiments, the dispersion or emulsion exhibits substantially no phaseseparation by visual inspection for at least 10, 15, 20, 25, or 30minutes, or even 1, 2, 3, 4, 5, or 6 hours or more after mixing thepolypeptide composition with the reactive prepolymer.

In another aspect, the invention provides an adhesive compositioncomprising (a) from about 5% to about 90% (w/w) of a reactiveprepolymer; and (b) from about 10% to about 90% (w/w) of an isolatedwater-soluble polypeptide composition comprising one or more of thefollowing features: (a) an amide-I absorption band between about 1633cm⁻¹ and 1680 cm⁻¹, as determined by solid state Fourier TransformInfrared Spectroscopy (FTIR); (b) an amide-II band between approximately1522 cm⁻¹ and 1560 cm⁻¹, as determined by solid state FTIR; (c) twoprominent 1° amide N—H stretch absorption bands centered at about 3200cm⁻¹ and at about 3300 cm⁻¹, as determined by solid state FTIR; (d) aprominent cluster of protonated nitrogen nuclei defined by ¹⁵N chemicalshift boundaries at about 94 ppm and at about 100 ppm, and ¹H chemicalshift boundaries at about 7.6 ppm and at about 8.1 ppm, as determined bysolution state, two-dimensional proton-nitrogen coupled NMR; (e) anaverage molecular weight of between about 600 and about 2,500 Daltons;(f) an inability to stabilize an oil-in-water emulsion, wherein, when anaqueous solution comprising 14 parts by weight of protein dissolved ordispersed in 86 parts by weight of water is admixed with 14 parts byweight of PMDI, the aqueous solution and the PMDI produce an unstablesuspension that macroscopically phase separates under static conditionswithin five minutes after mixing (See Example 34). Such adhesivesoptionally contain a catalyst, and the reactive prepolymer can be apoly-isocyanate-based prepolymer, an epoxy-based prepolymer, a latexprepolymer, or a combination thereof. The adhesive can be awater-soluble adhesive that facilitates the adherence of, for example,paper to solid support. Once wetted, the paper can be removed from thesolid support.

In each of the foregoing aspects of the invention, the organicpolyisocyanate can be selected from the group consisting of polymericdiphenylmethane diisocyanate (PMDI), 4,4′-methylenediphenyl,diisocyanate (4,4′-MDI), 2,4-methylenediphenyl, diisocyanate (2,4-MDI),or a combination thereof. Under certain circumstances, thepolyisocyanate-based reactive prepolymer is a polymer comprising one ormore terminal reactive isocyanate groups.

The polyol in the prepolymer composition can be an amine alkoxylate,polyoxypropylene glycol, polyoxyethylene glycol, polytetramethyleneglycol, polyethylene glycol, propylene glycol, propane diol, glycerin,or a mixture thereof.

When a catalyst is used, the catalyst can be a primary amine, asecondary amine, a tertiary amine, an organometallic compound, or acombination thereof. Exemplary primary amines include, for example,methylamine, ethylamine, propylamine, cyclohexylamine, and benzylamine.Exemplary secondary amines include, for example, dimethylamine,diethylamine, and diisopropylamine. Exemplary tertiary amines include,for example, diazabicyclooctane (Dabco), triethylamine, dimethylbenzylamine, bis-dimethylaminoethyl ether, tetramethyl guanidine,bis-dimethylaminomethyl phenol, 2,2′-dimorpholinodiethyl ether,2-(2-dimethylaminoethoxy)-ethanol,2-dimethylaminoethyl-3-dimethylaminopropyl ether,bis-(2-diaminoethyl)-ether, N,N-dimethyl piperazine,N-(2-hydroxyethoxyethyl)-2-azanorbornane, Tacat DP-914 (TexacoChemical), Jeffcat®, N,N,N,N-tetramethyl butane-1,3-diamine,N,N,N,N-tetramethyl propane-1,3-diamine,N,N,N,N-tetramethylhexane-1,6-diamine, 2,2′-dimorpholinodiethyl ether(DMDEE), or a mixture thereof. Exemplary organometallic compoundsinclude, for example, di-n-octyl tin mercaptide, dibutyl tin maleate,diacetate, dilaurate, dichloride, bis-dodecyl mercaptide,tin(II)acetate, ethyl hexoate and diethyl hexoate, Fe⁺³2,4-pentanedionate (FeAcAc), or lead phenyl ethyl dithiocarbamate.Further exemplary organometallic compounds include, for example, atransition metal acetylacetonates, e.g., an acetylacetonate compoundcomprising iron, copper, or nickel.

In each of the aspects of the invention, the isolated polypeptidecomposition can be derived from renewable agricultural biomass. Thestarting material for the isolated polypeptide composition, which can bea meal or a protein isolate, can be derived from one or more of corn,wheat, sunflower, cotton, rapeseed, canola, castor, soy, camelina, flax,jatropha, mallow, peanuts, algae, sugarcane bagasse, tobacco, whey, or acombination thereof.

Depending upon the processing steps employed, the polypeptidecomposition can comprise digested or hydrolyzed protein. Digestion canbe facilitated using one or more enzymes, and hydrolysis can befacilitated using one or more chemicals, for example, acid- oralkali-based hydrolysis. With regard to enzymatic hydrolysis, a numberof enzymes may be used including, for example, serine-, leucine-,lysine-, or arginine-specific proteases.

In certain embodiments, the isolated polypeptide composition is awater-insoluble/water dispersible protein fraction. However, dependingupon the method of isolation, the isolated polypeptide composition canalso contain water-soluble proteins. A water-insoluble/water dispersibleprotein fraction useful in making adhesives of the invention, inparticular, moisture resistant adhesives, comprises one or more of thefollowing features: (i) an amide-I absorption band between about 1620cm⁻¹ and 1632 cm⁻¹ and an amide-II band between approximately 1514 cm⁻¹and 1521 cm⁻¹, as determined by solid state FTIR, (ii) a prominent 2°amide N—H stretch absorption band centered at about 3272 cm⁻¹, asdetermined by solid state FTIR, (iii) an average molecular weight ofbetween about 600 and about 2,500 Daltons, (iv) two protonated nitrogenclusters defined by ¹⁵N chemical shift boundaries at about 86.2 ppm andabout 87.3 ppm, and ¹H chemical shift boundaries at about 7.14 ppm and7.29 ppm for the first cluster, and ¹H chemical shift boundaries atabout 6.66 ppm and 6.81 ppm for the second cluster, as determined bysolution state, two-dimensional proton-nitrogen coupled NMR, and (v) iscapable of dispersing an oil-in-water or water-in-oil to produce ahomogeneous emulsion that is stable for least 5 minutes.

In certain embodiments, the water-insoluble polypeptide composition isdispersible in water or other solvent and facilitates the dispersion ofoil-in-water or water-in-oil to produce a stable dispersion or a stableemulsion. The dispersion or emulsion exhibits substantially no phaseseparation by visual inspection for at least 5 minutes after mixing thepolypeptide composition with the oil. In certain embodiments, thedispersion or emulsion exhibits substantially no phase separation byvisual inspection for at least 10, 15, 20, 25, or 30 minutes, or even 1,2, 3, 4, 5, or 6 hours or more after mixing the polypeptide compositionwith the oil. Exemplary oils that can be emulsified or dispersed by theisolated polypeptide fraction include, for example, an organicpolyisocyanate (for example, PMDI, 4,4′-methylenediphenyl, diisocyanate(4,4′-MDI), 2,4-methylenediphenyl, diisocyanate (2,4-MDI),2,2-methylenediphenyl diisocyanate (2,2-MDI), monomeric MDI, or PMDIthat has been reacted with a hydroxyl-functional compound such as apolyol), mineral oil, soybean oil, derivatized soybean oil, motor oil,castor oil, derivatized castor oil, dibutyl phthalate, epoxidizedsoybean oil, corn oil, vegetable oil, caprylic triglyceride, Eucalyptusoil, tributyl o-acetylcitrate, linseed oil, an adipate ester, a sebacateester, a phthalate ester, and a citrate ester. Further exemplary oilsthat can be emulsified or dispersed by the isolated polypeptide fractioninclude, for example, an azelaic ester, a benzoate ester, a glycolderivative, an epoxy derivative, a phosphate ester. In an exemplaryassay, 14 parts (by weight) of a protein sample of interest is mixedwith 86 parts (by weight) of water and the resulting solution ordispersion is mixed with 14 parts (by weight) of oil, for example, PMDI(see Example 34). Under these conditions, the water-insoluble proteinfraction facilitates the creation of a dispersion or emulsion thatexhibits substantially no phase separation by visual inspection for atleast 5 minutes after mixing the polypeptide composition with the oil.The same assay can be conducted using the other oils.

The adhesive compositions of the invention, in addition to containing awater-insoluble/water dispersible protein fraction can also include awater-soluble protein fraction. Depending upon the composition of theadhesive, the ratio of the water-soluble protein fraction to thewater-insoluble/water dispersible polypeptide fraction ranges from 0:1to 3:2 (w/w). Alternatively, the weight ratio of thewater-insoluble/water dispersible polypeptide fraction to thewater-soluble protein fraction can be at least 1:1.

In another aspect, the invention provides an isolated polypeptidecomposition comprising a plurality of water-insoluble polypeptidesderived from a variety of starting materials including, for example,castor, soy, canola, corn, wheat, sunflower, cotton, rapeseed, camelina,flax, jatropha, mallow, peanuts, algae, sugarcane bagasse, tobacco orwhey, or a combination thereof. Where appropriate, the starting materialcan be a meal or a protein isolate derived from each of the foregoing.The isolated polypeptide composition is capable of dispersing oremulsifying an oil in water or water in oil. The oil can be selectedfrom the group consisting of an organic polyisocyanate (for example,PMDI, 4,4′-methylenediphenyl, diisocyanate (4,4′-MDI),2,4-methylenediphenyl, diisocyanate (2,4-MDI), 2,2-methylenediphenyl,diisocyanate (2,2-MDI), monomeric MDI, or PMDI that has been reactedwith a hydroxyl-functional compound such as a polyol), mineral oil,soybean oil, derivatized soybean oil, motor oil, castor oil, derivatizedcastor oil, dibutyl phthalate, epoxidized soybean oil, corn oil,vegetable oil, caprylic triglyceride, Eucalyptus oil, tributylo-acetylcitrate, linseed oil, an adipate ester, a sebacate ester, aphthalate ester, and a citrate ester. The isolated water-insoluble/waterdispersible polypeptide composition has a variety of applications, whichinclude, for example, dispersing an oil-based prepolymer in themanufacture of an adhesive or binder, dispersing an oil or plasticizerin the manufacture of a thermoplastic or thermosetting material,dispersing an oil for use in cosmetics or pharmaceuticals, or dispersingoils after an oil spill or during tertiary oil recovery.

The water-insoluble/water dispersible polypeptide composition comprisesone or more of the following features: (i) an amide-I absorption bandbetween about 1620 cm⁻¹ and 1632 cm⁻¹ and an amide-II band betweenapproximately 1514 cm⁻¹ and 1521 cm⁻¹, as determined by solid stateFTIR, (ii) a prominent 2° amide N—H stretch absorption band centered atabout 3272 cm⁻¹, as determined by solid state FTIR, (iii) an averagemolecular weight of between about 600 and about 2,500 Daltons(determined using, for example, MALDI mass spectrometry), (iv) twoprotonated nitrogen clusters defined by ¹⁵N chemical shift boundaries atabout 86.2 ppm and about 87.3 ppm, and ¹H chemical shift boundaries atabout 7.14 ppm and 7.29 ppm for the first cluster, and ¹H chemical shiftboundaries at about 6.66 ppm and 6.81 ppm for the second cluster, asdetermined by solution state, two-dimensional proton-nitrogen coupledNMR, and (v) is capable of emulsifying oil in water to produce ahomogeneous emulsion that is stable by visual inspection for least 5minutes.

In certain embodiments, the water-insoluble polypeptide composition iscapable of dispersing oil in water to produce a homogeneous emulsion ordispersion that is stable, by visual inspection, for at least 5 minutes.In certain embodiments, the dispersion or emulsion exhibitssubstantially no phase separation by visual inspection for at least 10,15, 20, 25, or 30 minutes, or even 1, 2, 3, 4, 5, or 6 hours aftermixing the polypeptide composition with the oil. The polypeptidecomposition is isolated by extraction under neutral or basic conditions,by enzyme digestion, or a combination thereof. Furthermore, thepolypeptide composition is substantially free of primary amines,carboxylic acids, amine salts, and carboxylate salts.

One or more of the isolated polypeptide composition can be used to makean adhesive composition, as described herein. Depending upon the proteinfractions used and/or the inclusion of certain additives, the resultingadhesives can be water-soluble or moisture resistant.

The adhesive composition can further include one or more compoundsselected from the group consisting of an organic polyisocyanate; areaction product between an organic polyisocyanate and, for example, apolypeptide, a polyol, an amine based polyol, an amine containingcompound, a hydroxy containing compound, or a combination thereof; anepoxy containing compound, a reaction product between an epoxycontaining compound and, for example, a polypeptide, a polyol, an aminebased polyol, an amine containing compound, a hydroxy containingcompound, or a combination thereof; an organosilane; a polymer latex; apolyurethane; and a mixture thereof.

In another aspect, the invention provides a method of producing awater-insoluble polypeptide composition capable of dispersing oremulsifying an oil in water or a water in oil. The method comprising thesteps of (a) incubating an aqueous solution comprising a dissolved ordispersed starting material, for example, canola meal, canola proteinisolate, castor meal, castor protein isolate, soy meal, or soy proteinisolate, or a combination thereof, at a pH in the range from about 6.5to about 13 for at least 5 minutes; (b), after step (a), reducing the pHto about 4.0-5.0 thereby to precipitate both a portion of water solubleprotein and water insoluble protein; (c) harvesting the proteinprecipitated in step (b); and (d) washing the protein harvested in step(c) thereby to produce an isolated polypeptide composition.

In certain embodiments, the method further comprises one or more of thefollowing steps: enzymatically digesting the meal or protein isolatebefore step (a), after step (a), or both before and after step (a);enzymatically digesting the precipitate produced in step (b);enzymatically digesting the polypeptide composition isolated in step(c); and enzymatically digesting the polypeptide composition isolated instep (d). In addition, the polypeptide composition can be used as isafter preparation or dried and stored until use. In addition, theinvention provides an isolated polypeptide composition produced by eachof the foregoing methods.

Furthermore, water-soluble protein, which can also be used in theadhesives of the invention, can be produced, for example, from thesupernatant produced in step (a), in step (b), etc.

In another aspect, the invention provides a stable emulsion ordispersion, for example, an aqueous emulsion or dispersion, comprisingfrom about 1% to about 90% (w/w) of an oil and from about 1% to about99% (w/w) of an isolated polypeptide composition, wherein the isolatedpolypeptide composition produces a stable emulsion or dispersion of theoil in an aqueous medium. The aqueous emulsion or dispersion optionallycomprises from about 1% to about 50% (w/w) of oil and from about 1% toabout 99% (w/w) of the isolated polypeptide composition. The isolatedprotein composition is capable of being dispersed in water and comprisesone or more of the following features: (i) an amide-I absorption bandbetween about 1620 cm-1 and 1632 cm-1 and an amide-II band betweenapproximately 1514 cm-1 and 1521 cm-1, as determined by solid stateFTIR, (ii) a prominent 2° amide N—H stretch absorption band centered atabout 3272 cm-1, as determined by solid state FTIR, (iii) an averagemolecular weight of between about 600 and about 2,500 Daltons(determined using, for example, MALDI mass spectrometry), (iv) twoprotonated nitrogen clusters defined by ¹⁵N chemical shift boundaries atabout 86.2 ppm and about 87.3 ppm, and ¹H chemical shift boundaries atabout 7.14 ppm and 7.29 ppm for the first cluster, and ¹H chemical shiftboundaries at about 6.66 ppm and 6.81 ppm for the second duster, asdetermined by solution state, two-dimensional proton-nitrogen coupledNMR, and (v) is capable of dispersing an oil in water to produce ahomogeneous emulsion that is stable for least 5 minutes. The oil can beselected from the group consisting of an organic polyisocyanate (forexample, PMDI, 4,4′-methylenediphenyl, diisocyanate (4,4′-MDI),2,4-methylenediphenyl, diisocyanate (2,4-MDI), 2,2-methylenediphenyl,diisocyanate (2,2-MDI), monomeric MDI, or PMDI that has been reactedwith a hydroxyl-functional compound such as a polyol), mineral oil,soybean oil, derivatized soybean oil, motor oil, castor oil, derivatizedcastor oil, dibutyl phthalate, epoxidized soybean oil, corn oil,vegetable oil, caprylic triglyceride, Eucalyptus oil, tributylo-acetylcitrate, linseed oil, an adipate ester, a sebacate ester, aphthalate ester, and a citrate ester.

In certain embodiments, the polypeptide composition has a polydispersityindex (PDI) of between about 1 and 1.15. In certain other embodiments,the polypeptide composition has a polydispersity index (PDI) of betweenabout 1 and 1.75, or between about 1 and 3. In certain embodiments, theemulsion exhibits substantially no phase separation by visual inspectionfor at least 5 minutes after mixing the polypeptide composition with theoil. In addition, the invention provides an adhesive compositioncomprising the stable emulsions described herein.

In another aspect, the invention provides a method of bonding a firstarticle to a second article. The method comprises the steps of (a)depositing on a surface of the first article any one of the foregoingadhesive compositions thereby to create a binding area; and (b)contacting the binding surface with a surface of the second articlethereby to bond the first surface to the second surface. The methodoptionally also comprises the step of, after step (b), permitting theadhesive composition to cure, which can be facilitated by theapplication of pressure, heat or both pressure and heat.

In another aspect, the invention provides a method of producing acomposite material. The method comprises the steps of (a) combining afirst article and a second article with any one of the foregoingadhesive compositions to produce a mixture; and (b) curing the mixtureproduced by step (a) to produce the composite material. The curing cancomprise applying pressure, heat or both pressure and heat to themixture.

In certain embodiments, the first article, the second article or boththe first and second articles are lignocellulosic materials, orcomposite materials containing lignocellulosic material. The firstarticle, the second article or both the first and second articles cancomprise a metal, a resin, a ceramic, a polymer, a glass or acombination thereof. The first article, the second article, or both thefirst article and the second article can be a composite. In addition,the invention provides an article produced by each of the foregoingmethods of manufacture.

In addition, the invention provides an article comprising two or morecomponents bonded together using one or more of the adhesivecompositions described herein. The bonded components can be selectedfrom the group consisting of paper, wood, glass, metal, fiberglass, woodfiber, ceramic, ceramic powder, plastic (for example, a thermosetplastic), and a combination thereof. The invention provides an article(for example, a composite material, laminate, or a laminate containingcomposite material) produced using one or more of the adhesivecompositions described herein.

The composite material can be chip board, particle board, fiber board,plywood, laminated veneer lumber, glulam, laminated whole lumber,laminated composite lumber, composite wooden I-beams, medium densityfiberboard, high density fiberboard, extruded wood, or fiberglass. Thecomposite can be a thermosetting composite or a thermoplastic composite.

In certain embodiments, the article comprises a lignocellulosiccomponent. Furthermore, the article can comprise paper, wood, glass,fiberglass, wood fiber, ceramic, ceramic powder, or a combinationthereof. In certain embodiments, the adhesive can comprise an organicpolyisocyanate, for example, from about 30% to about 70% (w/w) of anorganic polyisocyanate. In certain embodiments, polyisocyanate forms apolyurethane that comprises from about 1% to about 25% (w/w) of thearticle.

Depending upon the adhesive used, the resulting article can have one ormore of the following features: the article is moisture resistant; thearticle remains intact after boiling in water for 5 minutes; two or morecomponents of the article remain bonded after boiling in water for 5minutes; the article, when boiled in water for 5 minutes, displays lessthan a 20% increase in volume relative to the article prior to exposureto the water; and when the article (for example, a composite material,laminate, or a laminate containing a composite material) contains alignocellulosic material in the composite material or laminate, thearticle exhibits no less than 50%, optionally no less than 75%, cohesivefailure of the lignocellulosic component when the article is placedunder a loading stress sufficient to break the article. In certainembodiments, the article exhibits no less than 50% cohesive failure ofthe lignocellulosic component when the article is placed under a loadingstress sufficient to break the article.

These and other aspects and features of the invention are described inthe following detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will become apparent from the following description ofpreferred embodiments, as illustrated in the accompanying drawings. Likereferenced elements identify common features in the correspondingdrawings. The drawings are not necessarily to scale, with emphasisinstead being placed on illustrating the principles of the presentinvention, in which:

FIG. 1 is a flow chart showing adhesives that can be produced using theisolated polypeptide fractions described herein;

FIG. 2 is a flow chart showing the steps of an exemplary method forproducing isolated polypeptide compositions useful in the practice ofthe invention;

FIG. 3 is a graph showing the relationship between the concentration ofthe water-insoluble/water dispersible protein and the performance of anadhesive (or binder) produced using the protein;

FIG. 4 shows overlaid solid state FTIR spectra for protein materialsused in Example 18; namely digested and deaminated castor protein lot5-82, digested castor lot 5-83, and digested soy protein lot 5-81;

FIG. 5 shows overlaid solid state FTIR spectra for protein fractionsisolated from digested castor lot 5-90, and then used to prepareadhesives reported in Example 20; namely, the water-soluble fraction,and the water-insoluble, dispersible fraction;

FIG. 6 shows solid state FTIR spectra of isolated water-solublefraction, and water-insoluble/water dispersible fraction from digestedcastor, where the carbonyl amide region from FIG. 5 is expanded;

FIG. 7 shows solid state FTIR spectra of isolated water-solublefraction, and water-insoluble, dispersible fraction from digested castorwhere the N—H stretching region from FIG. 5 is expanded;

FIG. 8 shows the temperature of the center bond-line of the 7-plycomposite 6×6″ of Example 23;

FIG. 9 shows overlaid solid state FTIR spectra of isolated water-solublefraction, and water-insoluble/water dispersible fraction from castorprotein (lot 5-94), showing an expansion of the carbonyl amide region;

FIG. 10 shows the solid state FTIR spectra of isolated water-solublefraction, and water-insoluble/water dispersible fraction from castorprotein (lot 5-94), where the N—H and O—H stretch regions are expanded;

FIG. 11 shows overlaid solid state FTIR spectra of the isolatedwater-insoluble/water dispersible fractions from castor protein (lot5-94) and from enzyme digested castor (lot 5-90);

FIG. 12 shows overlaid solid state FTIR spectra of isolatedwater-soluble fraction, and water-insoluble, dispersible fraction fromdigested soy, where the carbonyl amide region is expanded, and where thespectra were vertically scaled to achieve equivalent absorbanceintensities for the amide-I carbonyl stretch;

FIG. 13 shows overlaid solid state FTIR spectra of isolatedwater-soluble fraction, and water-insoluble/water dispersible fractionfrom digested soy, where the N—H stretching region is expanded;

FIG. 14 shows overlaid solid state FTIR spectra of isolatedwater-insoluble polypeptide fractions from digested soy and digestedcastor;

FIG. 15 shows overlaid solid state FTIR spectra of isolatedwater-soluble polypeptide fractions from digested soy and digestedcastor;

FIG. 16 shows overlaid solid state FTIR spectra of isolatedwater-insoluble fractions from digested soy and soy flour;

FIG. 17 shows an solid state FTIR subtraction spectrum—(spectrum ofwater-insoluble fraction from soy flour)—(spectrum of water-insolublefraction from digested soy) illustrating the additional components thatwere observed to be present in the water-insoluble extract from soyflour;

FIG. 18 shows overlaid solid state FTIR surface ATR spectra of theisolated water-insoluble/dispersible fractions from multiple proteinsamples (digested soy lot 5-81, soy flour, castor protein isolate lot5-94, digested castor lot 5-90) where the carbonyl amide region isexpanded;

FIG. 19 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum for digestedcastor (lot 5-83) in d6-DMSO, showing two regions of interest denotedRegion A and Region B;

FIG. 20 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum forwater-insoluble/dispersible polypeptide fraction derived from digestedcastor (lot 5-83) in d6-DMSO, again showing Region A and Region B; and

FIG. 21 is a two-dimensional HSQC ¹H-¹⁵N NMR spectrum, where Region Afrom FIG. 20 has been magnified.

DETAILED DESCRIPTION

The invention provides emulsions, dispersions and adhesives that containa polypeptide composition (protein fraction) isolatable from a varietyof starting materials, including, for example, renewable plant biomass.An important component that facilitates production of the emulsions,dispersions, and adhesives is the particular polypeptide compositionisolated from the plant biomass. Because the starting material for thepolypeptide composition generally is a waste by-product from theagricultural industry that typically is incinerated or discarded, theinvention provides commercially useful emulsions, dispersions, andadhesives that also are environmentally friendly.

Certain polypeptide compositions described herein, for example, theisolated water-insoluble/water dispersible protein fractions, can beused to disperse or emulsify oils in water or water in oil. As a result,such polypeptide compositions can be used to disperse oils commonly usedin the manufacture of adhesives and, as such, can provide significantbenefits to the adhesive industry as well as to industries that uselarge volumes of adhesive. Up till now, it has been difficult to costeffectively produce large volumes of non-formaldehyde containing, highperformance glues, such as urea formaldehyde and phenol formaldehydeadhesives. Although it has been possible to produce high performanceglues using isocyanates, the cost associated with such adhesives hasprevented their widespread adoption into industries that use largevolumes of adhesives, for example, the wood composite industry. Thepolypeptide fractions described herein, however, address this long feltneed because, under certain circumstances, they permit the manufactureof high performance adhesives that use much less isocyanate thancurrently available isocyanate-based high performance glues.Furthermore, an additional advantage is that the polypeptide fractionsdescribed herein permit the dispersion of isocyanates, for example,PMDI, into large volumes that make it easy to apply the resultingadhesives over large surfaces, which may be needed, for example, in thewood composite industry.

In addition, the isolated water-soluble protein fractions can be used tomanufacture water-soluble adhesives. These adhesives are particularlyuseful when it is desirable to dissolve the adhesive and permit theseparation of previously bonded articles. In one embodiment, thewater-soluble adhesives can be used to stick paper onto a solid support,for example, glass (for example, a bottle or jar).

The invention provides both single-pot, one-part adhesives (a singlemixture that, without the addition of other components, functions as anadhesive) or two- or multi-part adhesives (adhesives created by mixingtogether two or more parts, which when mixed together function as anadhesive).

FIG. 1 shows a variety of one-part and two-part adhesives that can beproduced using the water-insoluble/water dispersible protein fractionsdescribed herein.

For example, a first type of one-part adhesive (denoted a Type-1adhesive) can be produced by mixing either i) isolated, fractionatedwater-insoluble/water dispersible proteins, or ii) isolated,fractionated, water-soluble proteins, or iii) a mixture of thereof, witha diisocyanate-based prepolymer, a polymeric isocyanate-basedprepolymer, an epoxy-based prepolymer or a combination thereof in thepresence of other optional additives (for example, a catalyst). Forexample, such one-part adhesives can be made by reacting PMDI with apolypeptide composition described above. As described in more detailbelow, these one-part adhesives can further comprise a polyol that isco-reacted with the PMDI and the polypeptide at the same time in onepot, or reacted in sequence by sequential addition into a single pot.Such compositions can serve as stand-alone one-part adhesives, or can beused as the Part-A component in a two-part system. A second type ofone-part adhesive (denoted a Type-2 adhesive) can be produced by mixingeither i) isolated, fractionated water-insoluble/water dispersibleproteins, or ii) isolated, fractionated, water-soluble proteins, or iii)a mixture of thereof, with a formulated polyurethane in the presence ofother optional additives. A third type of one-part adhesive (denoted aType-3 adhesive) can be produced by mixing either i) isolated,fractionated water-insoluble/water dispersible proteins, or ii)isolated, fractionated, water-soluble proteins, or iii) a mixture ofthereof, with a latex polymer in the presence of other optionaladditives. A fourth type of one-part adhesive (denoted a Type-4adhesive) can be produced by mixing either i) isolated, fractionatedwater-insoluble/water dispersible proteins, or ii) isolated,fractionated, water-soluble proteins, or iii) a mixture of thereof, withother optional additives. One embodiment of a Type-4 adhesive is awater-soluble adhesive that contains the water-soluble proteincomposition with other optional additives. These adhesives can be used,for example, to adhere paper to glass. Another embodiment of a Type-4adhesive is a water-insoluble adhesive that contains the water-solubleprotein composition with other optional additives. Depending upon theircomposition, each of the one-part adhesives (i.e., each of the Type-1,Type-2, Type-3, or Type-4 adhesives) can be used as an adhesive withoutthe addition of other components.

However, two-part adhesives, for example, as shown in FIG. 1, can beprepared by mixing together two or more of the one-part adhesives. Theone-part adhesives used in these applications are stable on their ownbut when mixed with second, different one-part adhesive, the resultingmixture creates an adhesive composition. Exemplary two-part adhesives,as shown in FIG. 1, can be created by combining (i) the Type 1 and Type3 adhesives to produce a fifth type of adhesive (denoted Type-5adhesive), (ii) the Type 2 and Type 4 adhesives to produce a sixth typeof adhesive (denoted Type-6 adhesive); (iii) the Type 1 and Type 4adhesives to produce a seventh type of adhesive (denoted Type-7adhesive), and (iv) the Type 2 and Type 3 adhesives to produce an eighttype of adhesive (denoted Type-8 adhesive).

As will be discussed in more detail below, the adhesives describedherein can be used in the production of a variety of wood based productsincluding composite materials, laminates, and laminates that containcomposite materials. For example, the adhesives can be used in theproduction of consolidated wood composites, for example, chipboard (alsoknown as OSB), fiberboard, and related composite wood products, as wellas in the in the production of engineered lumber composites, forexample, I-beams (I-joists), laminated veneer lumber (LVL), and othertypes of structural lumber composites.

By way of example, the adhesives described herein, for example, thepolyisocyanate containing adhesives, have a number of importantadvantages in the production of wood-based (lignocellulosic) compositesrelative to other commonly used wood adhesives. The advantages includehigher moisture tolerance and the lack of formaldehyde emissions.Unfortunately, polyisocyanate-based resins generally are more expensivethan formaldehyde-based resins. As a result, the cost penalty haslimited the penetration of isocyanate-based adhesives into major sectorsof the commodity wood products industry, which include the particleboardsector, the plywood sector, or the fiberboard sector. The adhesivesdescribed herein, by including high concentrations of thewater-insoluble/water dispersible protein and a lower amount ofpolyisocyanate, permit the manufacture of adhesives that perform as wellas or better than conventional adhesives that contain higher amounts ofpolyisocyanate. As a result, the resulting adhesives permit highadhesive loading without adversely affecting overall costs of the finalproduct.

Furthermore, in addition to their use in adhesives, thewater-insoluble/water dispersible proteins described herein can be usedto disperse or emulsify oils during the clean up of oil spills or duringtertiary oil recovery. In addition, the water-insoluble proteinfractions can also be used in the cosmetic, food and pharmaceuticalindustries in applications that require the emulsification or dispersionof oils.

The following sections describe the isolation and characterization ofpolypeptide compositions useful in making emulsions, dispersions andadhesives, the choice of suitable prepolymers and other additives thatcan be combined with the polypeptide compositions, methods for makingemulsions, dispersions and adhesives, as well as certain applicationsand uses of the emulsions, dispersions and adhesives described herein.

I. Isolation and Charaterization of Polypeptide Fractions

Different protein fractions derivable from renewable plant biomass havedifferent compositions, and as a result can be used in a variety ofdifferent applications. For example, the water-insoluble/waterdispersible protein fractions can be used to disperse or emulsify an oilin water or water in oil. As a result, these protein fractions can beused to disperse conventional oils (for example, reactive oils, or anorganic polyisocyanate, which is a reactive prepolymer) that are used tomake water and moisture resistant adhesives. These protein fractions canalso be used alone or with optional additives such as polymer latexes toform moisture resistant adhesives (such as to adhere a paper label to aglass bottle or jar). Alternatively, the water soluble protein fractionscan also be used to make water soluble adhesives that dissolve in water.Such adhesives, as described below, can optionally contain additives. Asa result, these adhesives can be used to, for example, adhere paper toglass (for example, to adhere a paper label to a glass bottle or glassjar, or to adhere an inspection sticker to a windshield). In addition,the water-insoluble/water-dispersible protein fraction as well as thewater-soluble protein fraction can be used in the synthesis of foams,which are described in detail in U.S. patent application Ser. No.12/719,721, filed on Mar. 8, 2010, the disclosure of which isincorporated by reference herein.

The terms “protein” and “polypeptide” are used synonymously and refer topolymers containing amino acids that are joined together, for example,via peptide bonds or other bonds, and may contain naturally occurringamino acids or modified amino acids. The polypeptides can be isolatedfrom natural sources or synthesized using standard chemistries. Thepolypeptides may be modified or derivatized by either natural processes,such as post-translational processing, or by chemical modificationtechniques well known in the art. Modifications or derivatizations mayoccur anywhere in the polypeptide, including, for example, the peptidebackbone, the amino acid side-chains and the amino or carboxyl termini.Modifications include, for example, cyclization, disulfide bondformation, demethylation, deamination, formation of covalentcross-links, formation of pyroglutamate, formylation,gamma-carboxylation, glycosylation, GPI anchor formation, hydroxylation,iodination, methylation, myristolyation, oxidation, pegylation,proteolytic digestion, phosphorylation, etc. As used throughout, theterm “isolated” refers to material that is removed from its originalenvironment (e.g., the natural environment if it is naturallyoccurring).

The starting material for producing the isolated polypeptidecompositions (which can be a meal or a protein isolate) can be derivedfrom one or more of corn, wheat, sunflower, cotton, rapeseed, canola,castor, soy, camelina, flax, jatropha, mallow, peanuts, algae, sugarcanebagasse, tobacco, or whey. It is understood that thewater-insoluble/water dispersible protein fraction can be produced by anumber of approaches, which are described in detail throughout theExamples. A crude water-insoluble/water dispersible protein fraction canbe isolated from caster meal by washing with water to removewater-soluble proteins and water-soluble components from the mixture(see Example 29). Alternatively, a crude water-insoluble/waterdispersible protein fraction can be isolated from, for example, soyprotein isolate or from soy flour by washing with water to removewater-soluble proteins and water-soluble components from the respectivesoy protein isolate or the water-flour mixture. Although the crudewater-insoluble/water dispersible protein fraction can disperse a numberof oils (see Example 29), depending upon the particular application itcan be advantageous to isolate a more pure form of thewater-insoluble/water dispersible protein fraction (see Example 34). Oneapproach for preparing the water-insoluble/water dispersible proteinfraction is shown schematically in FIG. 2.

As shown in FIG. 2, the starting material (for example, ground meal) isdispersed in alkaline, aqueous media at pH 6.5-13 for at least 5minutes, at least 20 minutes, at least 40 minutes or at least 1 hour, toform a mixture. Starting materials include, for example, canola meal,canola protein isolate, castor meal, castor protein isolate, soy meal,or soy protein isolate, or a combination thereof. Then, the pH of themixture is lowered by the addition of acid (to provide a mixture with apH in the range of, for example, 4.0-5.0) to precipitate both a portionof water-soluble proteins and water-insoluble proteins. Then, thewater-insoluble material (i.e., the precipitate) is harvested. Theharvested material is washed with water and the remainingwater-insoluble/water dispersible material is harvested. An exemplarylarge scale procedure is exemplified Example 31. In addition, as shownin FIG. 2, the water-soluble proteins can be harvested at a number ofplaces, for example, after the starting material is mixed in aqueousmedia, after neutralization, and as a supernatant from the washingsteps. The resulting protein can be used as is or dried using dryingtechniques known in the art.

It is understood that the process can also include one or more enzymedigestion and/or chemical hydrolysis steps. Digestion can be facilitatedusing one or more enzymes, and hydrolysis can be facilitated using oneor more chemicals, for example, acid- or alkali-based hydrolysis. Forexample, the starting material (for example, the ground meal) can beexposed to enzymatic digestion before or after, or both before and afterthe incubation of the starting material in the alkaline aqueous media.Alternatively, or in addition, an enzymatic digestion step can beperformed on the material following addition of acid to provide amixture with a pH in the range of 4.0 to 5.0. Alternatively, or inaddition, the harvested water-insoluble/water dispersible material afterharvesting can be exposed to enzymatic digestion prior to washing.Alternatively, or in addition, the material harvested after washing canbe exposed to enzymatic digestion. Chemical hydrolysis, however, canoccur with or replace the enzymatic digestion steps noted above.

Under certain circumstances residual basic species and alkali metalspresent in chemically digested proteins are not compatible withpolyisocyanates and can cause trimerization of the isocyanate groups,leading to stability problems in the final polyisocyanate compositions.Enzymatic digestion, however, can be used to avoid or reduce isocyanatestability problems associated with some chemical hydrolysis steps.

It is understood that enzymes useful in the digestion of the proteinfractions include endo- or exo-protease of bacterial, fungal, animal orvegetable origin or a mixture of thereof. Useful enzymes include, forexample, a serine-, leucine-, lysine-, or arginine-specific protease.Exemplary enzymes include trypsin, chymotrypsins A, B and C, pepsin,rennin, microbial alkaline proteases, papain, ficin, bromelain,cathepsin B, collagenase, microbial neutral proteases, carboxypeptidasesA, B and C, camosinase, anserinase, V8 protease from Staphylococcusaureus and many more known in the art. Also combinations of theseproteases may be used.

Also commercially available enzyme preparations such as, for example,Alcalase®, Chymotrypsine 800s, Savinase®, Kannase®, Everlase®,Neutrase®, Flavourzyme® (all available from Novo Nordisk, Denmark),Protex 6.0L, Peptidase FP, Purafect®, Purastar OxAm®, Properase®(available from Genencor, USA), Corolase L10 (Rohm, Germany), Pepsin(Merck, Germany), papain, pancreatin, proleather N and Protease N(Amano, Japan), BLAP and BLAP variants available from Henkel, K-16-likeproteases available from KAO, or combinations thereof. Table 1 describesthe amino acid specificity of certain useful endonucleases.

TABLE 1 No Amino Acid Notation Commercial Endopeptidase(s) 1 Alanine APronase ®; Neutrase ®: 2 Cysteine C Papain 3 Aspartic D Fromase ®; 4Glutamic E Alcalase ®; 5 Phenylalanine F Neutrase ®: Fromase ® 6 GlycineG Flavorzyme ®; Neutrase ®: 7 Histidine H Properase ®; 8 Isoleucine INeutrase ®: 9 Lysine K Alcalase ®; Trypsin; Properase ® 10 Leucine LAlcalase ®; Esperase ®; Neutrase ®: 11 Methionine M Alcalase ®;Neutrase ®: 12 Asparigine N Savinase ®; Flavourzyme ®; Duralase ®; 13Proline P Pronase ®; Neutrase ®: 14 Glutamine Q Alcalase ® 15 Arginine RTrypsin; Properase ®; 16 Serine S Savinase ®; Flavourzyme ®; Duralase ®;17 Threonine T Savinase ®; Flavourzyme ®; Duralase ®; 18 Valine VNeutrase ®: 19 Tryptophane W Neutrase ®: Fromase ® 20 Tyrosine YAlcalase ®; Esperase ®; Fromase ®

Depending upon the choice enzyme(s), enzymatic digestion usually isconducted under aqueous conditions at the appropriate pH conditions (forexample, depending upon the enzyme or enzyme mixture at neutral or atlow pH). In certain digestion systems, the digestion optimally occurs ata pH less than 9, or less than 8. For certain applications the pH of theaqueous protein digestion system is in the range of 3-9, 4-8 or 5-7.5.

Once digestion has proceeded to the desired extent, the resultingproduct optionally is washed and used as is or dried to form a powder.The drying can be performed by techniques known in the art, includingspray drying, freeze drying, oven drying, vacuum drying, or exposure todesiccating salts (such as phosphorous pentoxide or lithium chloride).

The water-insoluble/water dispersible material produced according to thepreferred method in FIG. 2 can disperse or emulsify oil in water orwater in oil. The physical and chemical properties of thewater-soluble/water dispersible fraction are described in more detailbelow. The resulting water-soluble protein fraction can be used as awater-soluble adhesive, for example, attaching paper to a substrate, forexample, a glass jar or bottle (see Example 21). The physical andchemical properties of the water-soluble protein fraction are describedin more detail below.

In certain embodiments, the proteins in the isolated protein fractionsare further derivatized. Suitable processes for derivatization of thepolypeptide fractions are provided in the literature. The nature andextent of modification will depend in large part on the composition ofthe starting material. The derivative can be produced by, for example,replacing at least a portion of primary amine groups of said isolatedprotein with hydroxyl groups, deaminating the protein, or replacing aportion of amide groups of the protein with carboxyl groups, etc. Inother embodiments, the isolated polypeptide compositions describedherein are obtained by reacting the protein with protein modifyingagents, for example, nitrous oxide, nitrous acid, salts of nitrous acid,or a combination thereof.

A. Characterization of the Water-Insoluble/Water Dispersible ProteinFraction

As discussed, one of the unexpected properties of thewater-insoluble/water dispersible protein fraction is that it is capableof dispersing oil in water or water in oil (see Examples 30, 33 and 34).The protein fraction that has these properties generally includes one ormore of the following features: (i) an amide-I absorption band betweenabout 1620 cm⁻¹ and 1632 cm⁻¹ and an amide-II band between approximately1514 cm⁻¹ and 1521 cm⁻¹, as determined by solid state FTIR, (ii) aprominent 2° amide N—H stretch absorption band centered at about 3272cm⁻¹, as determined by solid state FTIR, (iii) an average molecularweight of between about 600 and about 2,500 Daltons (determined using,for example, MALDI mass spectrometry), (iv) two protonated nitrogenclusters defined by ¹⁵N chemical shift boundaries at about 86.2 ppm andabout 87.3 ppm, and ¹H chemical shift boundaries at about 7.14 ppm and7.29 ppm for the first cluster, and ¹H chemical shift boundaries atabout 6.66 ppm and 6.81 ppm for the second cluster, as determined bysolution state, two-dimensional proton-nitrogen coupled NMR.

As described above, water-insoluble/water dispersible fraction iscapable of suspending or emulsifying oil in water or water in oil toproduce a homogeneous suspension or emulsion stable, by visualinspection, for least 5 minutes. In certain embodiments, the dispersionor emulsion exhibits substantially no phase separation by visualinspection for at least 10, 15, 20, 25, or 30 minutes, or even 1, 2, 3,4, 5, 6, 9, 12, 18, 24 hours after mixing the polypeptide compositionwith the oil. As shown in Example 34, the water-insoluble/waterdispersible fraction is capable of emulsifying or dispersing a wideselection of oils, including, for example, an organic polyisocyanate(for example, PMDI) mineral oil, soybean oil, derivatized soybean oil,motor oil, castor oil, derivatized castor oil, dibutyl phthalate,epoxidized soybean oil, corn oil, vegetable oil, caprylic triglyceride,Eucalyptus oil, and tributyl o-acetylcitrate. In an exemplary assay, 14parts (by weight) of a protein sample of interest is mixed with 86 parts(by weight) of water and the resulting solution or dispersion is mixedwith 14 parts (by weight) of oil, for example, PMDI. Under theseconditions, the water-insoluble/water dispersible protein fractionproduces a dispersion or emulsion exhibits substantially no phaseseparation by visual inspection for at least 5 minutes after mixing thepolypeptide composition with the oil. The assay can be performed withthe other oils.

In certain embodiments, the water-insoluble/water dispersible fractionis substantially free of primary amines, carboxylic acids, amine salts,and carboxylate salts.

The water-insoluble/water dispersible protein fraction can act as asurfactant to an organic polyisocyanate (e.g., PMDI), loweringinterfacial tension to the point where the water insoluble organicpolyisocyante is readily emulsified with minimal energy input, creatingan oil-in-water or water-in-oil emulsion. When the source material is awhole meal or a protein isolate derived from soy, castor or canola, astable emulsion can be obtained using undigested substantially insoluble(fractionated) protein. In certain embodiments, a stable emulsion ofpolyisocyanate (e.g., PMDI) in water can be achieved when the isolatedfractionated polypeptide is comprised of a water-insoluble/waterdispersible fraction, either alone, or in combination with a watersoluble component. The acceptable level of the water-soluble componentwill depend in large part upon the adhesive performance characteristicsthat are needed for the end-use application. The best overallcombination of adhesive performance properties (in terms of PMDIemulsification, bond strength, and water resistance) is achieved whenthe level of the water-soluble fraction is minimized, and when the levelof the water-insoluble dispersible fraction is maximized. For example,where high bond strengths and high degrees of moisture resistance aresimultaneously desired from an adhesive formulation as provided herein,the water-insoluble/water dispersible fraction comprises between about50%-100%, 50%-80%, 60%-100%, or 60%-90% (w/w) of the entire isolatedpolypeptide composition that is incorporated into the adhesiveformulation.

In applications where achieving high bond strengths and oil (e.g., PMDI)dispersibility in water are more important than maximizing moistureresistance, the water-insoluble/water dispersible fraction optionallycomprises no less than about 45% of the isolated polypeptide compositionthat is incorporated into the adhesive formulation. Under certaincircumstances, for example, an adhesive prepared with digested castorprotein extracted from castor meal, the process of isolating anddigesting a protein can lead to a polypeptide composition thatimplicitly contains both water-soluble and water-insoluble fractions atratios sufficient to simultaneously disperse oil in water while yieldinghigh bond strength adhesives. The process of digesting a whole meal canlead to a mixture that includes a polypeptide composition thatimplicitly contains both water-soluble and water-insoluble fractions atratios sufficient to simultaneously disperse oil in water while yieldinghigh bond strength adhesives (an example includes adhesives preparedwith digested whole castor meal). Where the process of digestion orextraction does not lead to a polypeptide composition that implicitlycomprises both water-soluble and water-insoluble fractions at ratioswhich are sufficient to simultaneously disperse oil in water whileyielding high bond strength adhesives, an additional fractionation stepcan be used to isolate sufficient levels of the water-insoluble/waterdispersible fraction from the polypeptide composition, so that the ratioof the water-insoluble fraction to the water-soluble fraction can beadjusted in the formulated adhesive for the purpose of achieving thedesired combination of end-use properties.

In certain embodiments, the polypeptide fractions used in thecompositions and methods provided herein, can have a weight averagemolecular weight of between about 500 and 25,000 Daltons. Usefulpolypeptide fractions can have a weight average molecular weight ofbetween about 500 and 2,500 Daltons, between about 700 and 2,300 Da.,between about 900 and 2,100 Da., between about 1,100 and 1,900 Da.,between about 1,300 and 1,700 Da., or between about 1,000 and 1,300 Da.,between about 2,000 and 2,500 Da., or between about 1,000 and 2,500 Da.

The isolated polypeptide composition can be used to make adhesivecompositions, as described herein, by combining them with a reactiveprepolymer. Reactive prepolymers can be selected from the groupconsisting of an organic polyisocyanate; a reaction product between anorganic polyisocyanate and a polypeptide, a polyol, an amine basedpolyol, an amine containing compound, a hydroxy containing compound, ora combination thereof; an epoxy containing compound; a reaction productbetween an epoxy containing compound and a polypeptide, a polyol, anamine based polyol, an amine containing compound, a hydroxy containingcompound, or a combination thereof, an organosilane; a polymer latex; apolyurethane; and a mixture thereof.

When making the adhesives, the isolated polypeptide composition, incertain embodiments, is capable of dispersing the reactive prepolymer inthe aqueous medium to produce a stable dispersion or a stable emulsion.The dispersion or emulsion exhibits substantially no phase separation byvisual inspection for at least 5 minutes after mixing the polypeptidecomposition with the reactive prepolymer. In certain embodiments, thedispersion or emulsion exhibits substantially no phase separation byvisual inspection for at least 10, 15, 20, 25, or 30 minutes, or even 1,2, 3, 4, 5, 6, 9, 12, 18, 24 hours after mixing the polypeptidecomposition with the reactive prepolymer.

In certain embodiments, the water-insoluble/water dispersible proteinfraction provides a stable emulsion, dispersion or suspension, forexample, an aqueous emulsion, dispersion or suspension, comprising fromabout 1% to about 90% (w/w) of an oil and from about 1% to about 99%(w/w) of an isolated polypeptide composition, wherein the isolatedpolypeptide composition produces a stable emulsion or dispersion of theoil in an aqueous medium. The aqueous emulsion, dispersion or suspensionoptionally comprises from about 1% to about 50% (w/w) of oil and fromabout 1% to about 99% (w/w) of the isolated polypeptide composition. Theterm “stable” when used in reference to the emulsions, suspensions anddispersions refers to the ability of the polypeptide fraction describedherein to create a kinetically stable emulsion for the duration of theintended application of the dispersion or emulsion. The terms“emulsion,” “dispersion,” and “suspension” are used interchangeablyherein.

In certain embodiments, the polypeptide composition has a polydispersityindex (PDI) of between about 1 and 1.15. In certain embodiments, the PDIof the adhesives provided created using the polypeptides describedherein is between about 1 and about 3, between 1 and 1.5, between 1.5and 2, between 2 and 2.5, between 2.5 and 3, between 1 and 2, between1.5 and 2.5, or between 2 and 3.

B. Characterization of Water-Soluble Protein Fraction

The water-soluble protein fractions, for example, the water-solubleprotein fractions isolated pursuant to the protocol set forth in FIG. 2,are substantially or completely soluble in water.

The water-soluble protein fractions have one or more of the followingsix features. (i) An amide-I absorption band between about 1633 cm⁻¹ and1680 cm⁻¹, as determined by solid state FTIR. (ii) An amide-II bandbetween approximately 1522 cm⁻¹ and 1560 cm⁻¹, as determined by solidstate FTIR. (iii) Two prominent 1° amide N—H stretch absorption bandscentered at about 3200 cm⁻¹, and at about 3300 cm⁻¹, as determined bysolid state FTIR. (iv) A prominent cluster of protonated nitrogen nucleidefined by ¹⁵N chemical shift boundaries at about 94 ppm and about 100ppm, and ¹H chemical shift boundaries at about 7.6 ppm and 8.1 ppm, asdetermined by solution state, two-dimensional proton-nitrogen coupledNMR. (v) An average molecular weight of between about 600 and about2,500 Daltons, for example, as determined by MALDI. (vi) An inability tostabilize an oil-in-water or water-in-oil dispersion or emulsion, wherethe water and oil components of the mixture form an unstable suspensionthat macroscopically phase separates under static conditions within fiveminutes after mixing. This can be tested by dissolving or dispersing 14parts (by weight) of a protein sample of interest in 86 parts (byweight) of water and then mixing the resulting solution with 14 parts(by weight) of oil, for example, PMDI. Under these conditions, awater-soluble protein is characterized by an inability to stabilize anoil-in-water emulsion, where the oil and water components form anunstable suspension that macroscopically phase separates under staticconditions within five minutes after mixing.

II. Prepolymer Considerations

When making suitable emulsions, dispersions, and adhesives, the proteinfractions described hereinabove can be combined with a reactiveprepolymer. The term “prepolymer” is understood to mean a compound,material or mixture that is capable of reacting with a polypeptidefraction described herein to form an adhesive polymer. Exemplaryprepolymers include, for example, isocyanate-based prepolymers,epoxy-based prepolymers, and latex prepolymers. Further, forillustration, the term “prepolymer” includes full prepolymers andpartial prepolymers (referred to as semiprepolymers, pseudoprepolymers,or quasiprepolymers in certain embodiments). One example of a quasiprepolymer is a NCO-terminated product prepared from a diisocyanate andpolyol in which the prepolymer is a mixture of (i) a product preparedfrom the diisocyanate and polyol, and (ii) unreacted diisocyanate. Onthe other hand, an example of a full prepolymer is the product formed byreacting an isocyanate with a particular polyol blend so that there aresubstantially no residual monomeric isocyanates in the finished product.

An isocyanate-based prepolymer can be an organic polyisocyanate, whichcan be (i) a polyisocyanate (or monomeric diisocyanate) that has notbeen reacted with another compound, (ii) a polyisocyanate modified byvarious known self-condensation reactions of polyisocyanates, such ascarbodiimide modification, uretonimine modification, trimer(isocyanurate) modification or a combination thereof, so long as themodified polyisocyanate still contains free isocyanate groups availablefor further reaction, or (iii) the product formed by reaction of apolyisocyanate base with a compound having nucleophilic functionalgroups capable of reacting with an isocyanate group. Exemplary compoundscontaining a nucleophilic functional group capable of reacting with anisocyanate group include a polypeptide (for example, one or more of theprotein fractions described herein), a polyol, an amine based polyol, anamine containing compound, a hydroxy containing compound, carboxylicacid containing compound, carboxylate salt containing compound, or acombination thereof. The term “polyisocyanate” refers to difunctionalisocyanate species, higher functionality isocyanate species, andmixtures thereof.

One desirable feature of an isocyanate-based prepolymer is that theprepolymer remain stable enough for storage and use, desirably liquidand of reasonable viscosity at ambient temperatures (25° C.), andcontains free isocyanate (—NCO) groups which can participate in formingadhesive bonds.

As noted above, the organic polyisocyanate can be prepared from a “basepolyisocyanate.” The term “base isocyanate” as used herein refers to amonomeric or polymeric compound containing at least two isocyanategroups. The particular compound used as the base polyisocyanate can beselected so as to provide an adhesive having certain desired properties.For example, base polyisocyanate can be selected based on thenumber-average isocyanate functionality of the compound. For example, incertain embodiments, the base polyisocyanate can have a number-averageisocyanate functionality of 2.0 or greater, or greater than 2.1, 2.3 or2.4. In certain embodiments, the reactive group functionality of thepolyisocyanate component ranges from greater than 1 to several hundred,2 to 20, or 2 to 10. In certain other embodiments, the reactive groupfunctionality of the polyisocyanate component is at least 1.9. Incertain other embodiments, the reactive group functionality of thepolyisocyanate component is about 2. Typical commercial polyisocyanates(having an isocyanate group functionality in the range of 2 to 3) may bepure compounds, mixtures of pure compounds, oligomeric mixtures (animportant example being polymeric MDI), and mixtures of these.

Useful base polyisocyanates have, in one embodiment, a number averagemolecular weight of from about 100 to about 5,000 g/mol, from about 120to about 1,800 g/mol, from about 150 to about 1,000 g/mol, from about170 to about 700 g/mol, from about 180 to about 500 g/mol, or from about200 to about 400 g/mol. In certain other embodiments, at least 80 molepercent or, greater than 95 mole percent of the isocyanate groups of thebase polyisocyanate composition are bonded directly to an aromaticgroup. In certain embodiments, the adhesives described herein have aconcentration of free organically bound isocyanate (—NCO) groups in therange of from about 5% to 35% (wt/wt), about 7% to 31% (wt/wt), 10% to25% (wt/wt), 10% to 20% (wt/wt), 15% to 27% (wt/wt).

In certain embodiments, the base polyisocyanate is an aromaticpolyisocyanate, such as p-phenylene diisocyanate; m-phenylenediisocyanate; 2,4-toluene diisocyanate; 2,6-toluene diisocyanate;naphthalene diisocyanates; dianisidine diisocyanate; polymethylenepolyphenyl polyisocyanates; 2,4′-diphenylmethane diisocyanate(2,4′-MDI); 4,4′-diphenylmethane diisocyanate (4,4′-MDI);2,2′-diphenylmethane diisocyanate (2,2′-MDI);3,3′-dimethyl-4,4′-biphenylenediisocyanate; mixtures of these; and thelike. In certain embodiments, polymethylene polyphenyl polyisocyanates(MDI series polyisocyanates) having a number averaged functionalitygreater than 2 are utilized as the base polyisocyanate.

In certain embodiments, the MDI base polyisocyanate comprises a combined2,4′-MDI and 2,2′-MDI content of less than 18.0%, less than 15.0%, lessthan 10.0%, or less than 5.0%.

In certain other embodiments, the MDI diisocyanate isomers, mixtures ofthese isomers with tri- and higher functionality polymethylenepolyphenyl polyisocyanates, the tri- or higher functionalitypolymethylene polyphenyl polyisocyanates themselves, and non-prepolymerderivatives of MDI series polyisocyanates (such as the carbodiimide,uretonimine, and/or isocyanurate modified derivatives) are utilized aspolyisocyanates for use as the base polyisocyanate. In certain otherembodiments, the base polyisocyanate composition comprises an aliphaticpolyisocyanate (e.g., in a minor amount), e.g., an aliphaticpolyisocyanate comprising an isophorone diisocyanate, 1,6-hexamethylenediisocyanate, 1,4-cyclohexyl diisocyanate, or saturated analogues of theabove-mentioned aromatic polyisocyanates, or mixtures thereof.

In certain other embodiments, the base polyisocyanate comprises apolymeric polyisocyanate, e.g., a polymeric diphenylmethane diisocyanate(polymethylene polyphenyl polyisocyanate) species of functionality 3, 4,5, or greater. In certain embodiments, the polymeric polyisocyanates ofthe MDI series comprise RUBINATE-M® polyisocyanate, or a mixture of MDIdiisocyanate isomers and higher functionality oligomers of the MDIseries. In certain embodiments, the base polyisocyanate product has afree —NCO content of about 31.5% by weight and a number averagedfunctionality of about 2.7.

In certain embodiments, the isocyanate group terminated prepolymers areurethane prepolymers. These can be produced by reaction of ahydroxyl-functional compound with an isocyanate functional compound. Incertain other embodiments, allophanate prepolymers are utilized.Allophanate prepolymers typically require higher temperatures (orallophanate catalysts) to facilitate reaction of the polyol with thepolyisocyanate to form the allophanate prepolymer.

Polyisocyanates used in the compositions described can have the formulaR(NCO)_(n), where n is 2 and R can be an aromatic, a cycloaliphatic, analiphatic, each having from 2 to about 20 carbon atoms. Examples ofpolyisocyanates include, but are not limited to,diphenylmethane-4,4′-diisoeyanate (MDI), toluene-2,4-diisocyanate (TDI),toluene-2,6-diisocyanate (TDI), methylene bis(4-cyclohexylisocyanate(Hi₂MDI), 3-isocyanatomethyl-3,5,5-trimethyl-cyclohexyl isocyanate(IPDI), 1,6-hexane diisocyanate (HD1), naphthalene-1,5-diisocyanate(NDI), 1,3- and 1,4-phenylenediisocyanate,triphenyImethane-4,4′,4″-triisocyanate, polymeric diphenylmethanediisocyanate (PMDI), m-xylene diisocyanate (XDI), 1,4-cyclohexyldiisocyanate (CHDI), isophorone diisocyanate, isomers, dimers, trimersand mixtures or combinations of two or more thereof. The term “PMDI”encompasses PMDI mixtures in which monomeric MDI, for example 4,4′-,2,2′- and/or 2,4′-MDI, is present. PMDI is, in one embodiment, preparedby phosgenation of the corresponding PMDA in the presence of an inertorganic solvent. PMDA is in turn obtained by means of an acidaniline-formaldehyde condensation which can be carried out industriallyeither continuously or batchwise. The proportions ofdiphenylmethanediamines and the homologouspolyphenylpolymethylenepolyamines and their positional isomerism in thePMDA are controlled by selection of the ratios of aniline, formaldehydeand acid catalyst and also by means of a suitable temperature andresidence time profile. High contents of 4,4′-diphenylmethanediaminetogether with a simultaneously low proportion of the 2,4′ isomer ofdiphenylmethanediamine are obtained on an industrial scale by the use ofstrong mineral acids such as hydrochloric acid as catalyst in theaniline-formaldehyde condensation.

The epoxy-based prepolymer can be an epoxide containing compound.Alternatively, the epoxy-based prepolymer can be a reaction productbetween an epoxy and a polypeptide, a polyol, an amine based polyol, anamine containing compound, a hydroxy containing compound, or acombination thereof.

In certain embodiments, the composition is an epoxy resin comprisingfree epoxy groups. Alternatively, the epoxy resin composition isprepared by combining a precursor epoxy resin composition with theisolated and fractionated polypeptide compositions described herein. Theepoxy resin composition can comprise derivatives of digested proteins asdescribed herein.

Epoxy resins refer to molecular species comprising two or more epoxide(oxirane) groups per molecule. Epoxy resins can contain mono-epoxides asreactive diluents, but the main constituents by weight of such resinsare still di and/or higher functionality species (containing two or moreepoxide groups per molecule).

Epoxy resins useful as precursor epoxy resins can include those whichcomprise difunctional epoxide and/or higher functionality polyepoxidespecies. Precursor epoxy resins include but are not limited todiglycidyl ether of bisphenol-A, diglycidyl ethers of bisphenol-Aalkoxylates, epoxy novolac resins, expoxidized soy oil, epoxidizedlinseed oil, epichlorohydrin, a glycidyl ether type epoxy resin derivedfrom a polyphenol by reaction with epichlorohydrin, and combinationsthereof. In another embodiment, precursor epoxy resins are modified bycombining them with the polypeptide compositions described herein,either in bulk or in aqueous suspension.

The modified epoxy resins can be used in multi-part mixing-activatedadhesive formulations. Alternatively, multi-part formulations cancomprise polyisocyanates and/or known amine based epoxy curatives asadditional components. Alternatively, modified epoxy resins can be usedwith any cure catalysts or other additives known in the epoxy resin art.The polypeptide compositions described herein contain functional groupswhich react with epoxide groups in the epoxy resin. The extent of thisreaction depends upon the preparative conditions, use or non-use ofcatalysts, the specific resins and fractionated and isolated polypeptidecompositions described herein selected, etc.

An important subset of epoxy resins can be made by reacting a precursorpolyol with an epihalohydrin, such as epichlorohydrin. The products ofthe reaction are called glycidyl ethers (or sometimes as polyglycidylethers or diglycidyl ethers). In certain embodiments, all the hydroxylgroups in the precursor polyols are converted to the correspondingglycidyl ethers.

An important class of glycidyl ether type epoxy resins are derived frompolyphenols, by reaction with epichlorohydrin. The starting polyphenolsare di- or higher functionality phenols. Industrially important examplesof this type of epoxy resin comprise, for example, diglycidyl ether ofbisphenol-A (also known as DGEB-A); diglycidyl ether of2,6,2′,6′-tetrachloro bisphenol A; diglycidyl ether of bisphenol-F(DGEB-F); epoxidized novolac resins; mixtures of these, and the like.

Partially or fully saturated (hydrogenated) analogs of these epoxyresins may also be used. A non limiting example of a known saturatedepoxy resin of this type is DGEB-H, which is the fully hydrogenated(ring saturated) aliphatic analog of DGEB-A.

Amines, which contain active hydrogen atoms may also be reacted withepichlorohydrin to form epoxy resins. Examples of these types of resinsinclude, for example, N,N,N′,N′-tetraglycidyl diphenylmethane diamine(such as the 4,4′ isomer); p-glycidyloxy-N,N-diglycidylaniline;N,N-diglycidylaniline; mixtures of these; and the like.

Heterocyclic nitrogen compounds that contain active hydrogen atoms maylikewise be converted into the corresponding epoxy resins by reactionwith epichlorohydrin. Non limiting examples of such resins include, forexample, N,N′,N″-triglycidyl isocyanurate;N,N′-diglycidyl-5,5-dimethylhydantoin; mixtures of these; and the like.

Many other kinds of epoxy resins are known which are not made byreaction of an active hydrogen precursor with an epihalohydrin.Non-limiting examples of these types of epoxy resins, known in the art,include, for example, dicyclopentadiene diepoxide (also known as DCPDdioxide), vinycyclohexene diepoxide (dioxide), epoxidizedpolyunsaturated vegetable oils (such as epoxidized linseed oil,epoxidized soy oil, etc.), epoxidized polydiene resins (such asepoxidized polybutadienes), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methyl cyclohexane carboxylate, mixtures ofthese, and the like. In principle, any precursor molecule which containstwo or more units of reactive aliphatic “C═C” unsaturation per moleculemight be converted into an epoxy resin.

It should be understood that any of the base epoxy resins known in theart, such as those listed above, are frequently modified with diluents,flexibilizers, and/or other additives. The optional possibility of usingone or more known art modifiers or additives, in addition to therequired protein derivatives, is within the level of skill in the art.Those skilled in the art of formulating adhesive systems using epoxyresins will appreciate how and when to use known optional additives andmodifiers.

In addition, the prepolymers can include one, two or more polyolcompounds. Exemplary polyol compounds include an amine alkoxylate,polyoxypropylene glycol, propylene glycol, polyoxyethylene glycol,polytetramethylene glycol, polyethylene glycol, propane diol, glycerin,or a mixture thereof.

Polyols useful in preparing the adhesives described herein include allknown polyols, for example, polyols used in the polyurethanes art. Incertain embodiments, the polyol comprises primary and/or secondaryhydroxyl (i.e., —OH) groups. In certain other embodiments, the polyolcomprises at least two primary and/or secondary hydroxyl (i.e., —OH)groups per molecule. Mono functional alcohols (such as aliphaticalcohols, aromatic alcohols, or hydroxyl functional monomers such ashydroxyl functional acrylates (to yield UV or thermally curablematerials) can be used to cap an isocyanate group. In certain otherembodiments, the polyol comprises a hydroxyl (i.e., —OH) groupfunctionality between 1.6 and 10, between 1.7 to 6, between 2 to 4, orbetween 2 to 3. In certain other embodiments, the weight averagemolecular weight range for the optional polyols is from 100 to 10,000g/mol, from 400 to 6,000 g/mol, or from 800 to 6,000 g/mol.

In certain other embodiments, useful polyols are polyester polyols orpolyether polyols, such as an aliphatic polyether polyol. One exemplaryaliphatic polyether polyol is polyoxypropylene glycol, with a numberaverage molecular weight in the range of from 1,500 to 2,500 g/mol.

In certain embodiments, the total amount of all polyol, or polyols, inthe isocyanate reactive component is from 1% to 80%, or from 3% to 70%,or from 5% to 60% by weight of the total.

In certain other embodiments, alkanolamines comprising primary,secondary, and/or tertiary amine groups can be used.

In certain embodiments, useful water dispersible polymer latexes caninclude latexes of polymethylmethacrylate and its copolymers, latexes ofpolymethacrylate and its copolymers, latexes of polyvinylchloride andits copolymers, latexes of polyvinylacetate and its copolymers,polyvinyl alcohol and its copolymers, etc.

Further, as discussed above, the prepolymer species can comprise aterminated isocyanate. Here, for example, a polyol is reacted with thebase polyisocyanate composition prior to or during mixing with thepolypeptide fractions herein. Those skilled in the art will recognizemany variations on the use of optional prepolymers in preparing woodadhesive compositions.

The amount of reactive prepolymer used in the adhesive compositions canbe selected based on the desired properties of the adhesive composition.For example, when optimizing the viscosity of a one-part adhesive, theratio of prepolymer (e.g., PMDI, Epoxy and the like) to isolatedpolypeptide composition can be from about 10:1 and 4:1 in order to forman adhesive composition that is relatively less viscous. Alternatively,for a two-part adhesive, the ratio of prepolymer (e.g., PMDI, Epoxy andthe like) to isolated polypeptide composition can be from about 1:20 to3:2.

III. Additional Additives

It is understood that the polypeptide fraction, the prepolymer, ormixtures formed from these components can be mixed with one or moreadditives depending upon the intended use. Exemplary additives includecatalysts, extenders, fillers, viscosifying agents, surfactants,adhesion promoters, antioxidants, antifoaming agents, antibacterialagents, fungicides, pigments, inorganic particulates, gelling agents,and cross-linking agents.

Exemplary catalysts include, for example, a primary amine, a secondaryamine, a tertiary amine, an organometallic compound, or a combinationthereof. Exemplary primary amines include, for example, methylamine,ethylamine, propylamine, cyclohexylamine, and benzylamine. Exemplarysecondary amines include, for example, dimethylamine, diethylamine, anddiisopropylamine. Exemplary tertiary amines include, for example,diazabicyclooctane (Dabco), triethylamine, dimethyl benzylamine,bis-dimethylaminoethyl ether, tetramethyl guanidine,bis-dimethylaminomethyl phenol, 2,2′-dimorpholinodiethyl ether,2-(2-dimethylaminoethoxy)-ethanol,2-dimethylaminoethyl-3-dimethylaminopropyl ether,bis-(2-diaminoethyl)-ether, N,N-dimethyl piperazine,N-(2-hydroxyethoxyethyl)-2-azanorbornane, Tacat DP-914 (TexacoChemical), Jeffcat®, N,N,N,N-tetramethyl butane-1,3-diamine,N,N,N,N-tetramethyl propane-1,3-diamine,N,N,N,N-tetramethylhexane-1,6-diamine, 2,2′-dimorpholinodiethyl ether(DMDEE), or a mixture thereof. Exemplary organometallic compoundsinclude, for example, di-n-octyl tin mercaptide, dibutyl tin maleate,diacetate, dilaurate, dichloride, bis-dodecyl mercaptide,tin(II)acetate, ethyl hexoate and diethyl hexoate, Fe⁺2,4-pentanedionate (FeAcAc), or lead phenyl ethyl dithiocarbamate.

In certain other embodiments, the catalyst is a transition metalacetylacetonates, e.g., an acetylacetonate compound comprising iron,copper, or nickel). In certain embodiments, the transition metalacetylacetonate comprises a tertiary amine, e.g., 2,2′-dimorpholinodiethyl ether).

The amount of catalyst used in the adhesive composition can be varied inorder to optimize the features of the adhesive. In certain embodiments,the catalyst is present in less than 1% (wt/wt), 0.5% (wt/wt), or 0.1%(wt/wt) of the adhesive composition. In certain other embodiments, thecatalyst is present in a range from 0.001% (wt/wt) to 0.75% (wt/wt),0.001% (wt/wt) to 0.01% (wt/wt), 0.01% (wt/wt) to 0.05% (wt/wt), or0.05% (wt/wt) to 0.5% (wt/wt) of the adhesive composition.

Exemplary extenders include, for example, inert extenders or activeextenders. In certain embodiments, the inert extender is vegetableparticulate matter, vegetable oil, mineral oil, dibasic esters,propylene carbonate, non-reactive modified aromatic petroleumhydrocarbons, and in general any non-active hydrogen containing liquidthat can be incorporated into an isocyanate based adhesive. The activeextender can be a pyrrolidone monomer or polymers, an oxizolidonemonomer or polymers, an epoxidized oil, or an unsaturated oil, such aslinseed oil.

Exemplary surfactants include, for example, monomeric types, polymerictypes, or mixtures thereof. Exemplary adhesion promoters include, forexample, organosilanes and titanates. Other additives include, forexample, antioxidants, antifoaming agents, anti-bacterial agents,fungicides, pigments, viscosifying agents, gelling agents, aereosolozingagents, inorganic particulates (e.g., titanium dioxide, yellow ironoxide, red iron oxide, black iron oxide, zinc oxide, aluminum oxide,aluminum trihydrate, calcium carbonate), clays such as montmorillonite,wetting agents, and the like.

In certain embodiments, the additive is a water-dispersible additive ora water-soluble additive. Water-soluble additives includehydroxyl-functional or amine-functional compounds (such as glycerin,urea, propylene glycol, polypropylene glycol, polyethylene glycol,trimethylol propane and its adducts, phenols, polyphenols, etc.) capableof reacting with a polymeric isocyanate, e.g., PMDI.

In other embodiments, the additive can be a crosslinking agent, forexample, a crosslinking agent that can be used to bond lignocellulosicmaterial to glass. Exemplary crosslinking agents include anorganosilane, such as dimethyldichlorosilane (DMDCS),alkyltrichlorosilane, methyltrichlorosilane (MTCS),N-(2-aminoethyl)-3-aminopropyl trimethoxysilane (AAPS), or a combinationthereof. In other embodiments the polypeptide fractions are combinedwith an organosilane to form an adhesive for bonding one or moresubstrates together in any combination, said substrates including glass,paper, wood, ceramic, steel, aluminum, copper, brass, etc. The term“organosilane” refers to any group of molecules including monomers,hydrolyzed monomers, hydrolyzed dimers, oligomers, and condensationproducts of a trialkoxysilane having a general formula:(RO)₃Si—R′where R is preferably a propyl, ethyl, methyl, isopropyl, butyl,isobutyl, sec-butyl, t-butyl, or acetyl group, and R′ is anorganofunctional group where the functionality may include anaminopropyl group, an aminoethylaminopropyl group, an alkyl group, avinyl group, a phenyl group, a mercapto group, a styrylamino group, amethacryloxypropyl group, a glycidoxy group, an isocyante group, orothers.

In certain other embodiments, the additive is a non-volatile (e.g.,having a boiling point of greater than about 180° C. at 760 mmHg), inertviscosity-reducing diluent.

Similarly, a bis-trialkoxysilane having the general formula(RO)₃Si—R′—Si(OR)₃ can also be employed as an “organosilane” eitheralone or in combination with a trialkoxysilane, where R is preferably apropyl, ethyl, methyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl,or acetyl group, and R′ is a bridging organofunctional residue which maycontain functionality selected from the group consisting of aminogroups, alky groups, vinyl groups, phenyl groups, mercapto groups, andothers. Similarly, a tetraalkoxysilane having the general formula(RO)₄Si can also be employed as an “organosilane” either alone or incombination with a trialkoxysilane, or a bis-trialkoxysilane, where R ispreferably a propyl, ethyl, methyl, isopropyl, butyl, isobutyl,sec-butyl, t-butyl, or acetyl group.

IV. Adhesive Compositions

It is understood that a variety of adhesives can be prepared using themethods and compositions described herein. The adhesives can be one-partadhesives or two-part adhesives, as shown in FIG. 1.

In one aspect, the invention provides an adhesive compositioncomprising: (a) from about 5% to about 90% (w/w) of a reactiveprepolymer; and (b) from about 10% to about 99% (w/w) of an isolatedpolypeptide composition capable of dispersing the reactive prepolymer inan aqueous medium, for example, water or a water-based solution.

A. One-Part Adhesives

The invention provides a variety of stand alone or one-part adhesives,as shown in FIG. 1. The one-part adhesives can be produced using thepolypeptide compositions, prepolymers and additives discussedhereinabove. In their simplest form, the one-part adhesives do notrequire any additional additives to cure and form an adhesive material.

In one embodiment, the invention provides an adhesive compositioncomprising: (a) from about 5% to about 90% (w/w) of a reactiveprepolymer selected from the group consisting of an organicpolyisocyanate, a reaction product between an organic polyisocyanate anda polypeptide, a polyol, an amine based polyol, an amine containingcompound, a hydroxy containing compound, or a combination thereof; (b)from about 10% to about 99% (w/w) of an isolated polypeptide compositioncapable of dispersing the reactive prepolymer in an aqueous medium; and(c) an optional catalyst. In certain other embodiments, the adhesivecomposition contains 10% to 99.9% of the polypeptide compositions, andis free of reactive isocyanate compounds. Such compositions optionallycomprise one or more additives, e.g., a water-soluble polymer,water-dispersible latex polymer, organosilane, or other water-soluble orwater-dispersible material.

In certain embodiments, isocyanate reactive component formulations areone-part adhesives. The one-part adhesives desirably are a liquid at 25°C. and stable to storage for at least one week (7 days) at 25° C., atleast two weeks at 25° C., at least one month at 25° C., or at leastthree months at 25° C.

The adhesives can be cured by allowing the adhesive to stand underambient conditions, or the adhesive may be cured by exposing theadhesive to heat, pressure, or both. Exemplary one-part adhesives aredescribed, for example, in Examples 1-8. Furthermore, in certainembodiments, these adhesives are stable but can cure when exposed to themoisture in air.

In certain embodiments, the one-part adhesive composition comprises noless than about 2%, 5%, 10%, or 15% by weight of the isolated andfractionated polypeptide described herein (based on the dry weight ofthe isolated and fractionated polypeptide described herein), relative tothe total polyisocyanate composition weight. The maximum loading of theisolated and fractionated polypeptide can be based on the amount of freeisocyanate (—NCO) groups in the final composition, as well as optimizingstability and viscosity sufficiently. In certain embodiments, the totalconcentration of isolated and fractionated polypeptide composition maybe of up to 35% (wt/wt). Higher viscosity compositions formed fromhigher weight percentages of the isolated and fractionated polypeptidedescribed herein can be beneficial in applications where it is desirablefor the uncured adhesive to exhibit cold-tack, flow resistance, sagresistance, and gap-filling characteristics.

B. Two- or Multi-Part Adhesives

In addition, the invention provides a variety of two- or multi-partadhesives as shown in FIG. 1. The two-part adhesives can be formed usingthe polypeptide compositions, prepolymers and additives discussed above.

The two-part adhesives require mixing two or more stable materials(mixtures) that upon mixing together produce an adhesive material. Suchcompositions are generally used within a short time period after mixingbecause the components may begin to react upon mixing. In oneembodiment, the invention provides a two-part adhesive compositioncomprising: (a) a first component (Part A) comprising from about 5% toabout 90% (w/w) of a reactive prepolymer, wherein the reactiveprepolymer is a polyisocyanate-based prepolymer, an epoxy-basedprepolymer, or a combination thereof and (b) a second component (Part B)comprising from about 10% to about 99% (w/w) of an isolated polypeptidecomposition capable of dispersing the reactive prepolymer in an aqueousmedium.

Depending upon the composition of Part A and Part B, Parts A and B aremixed immediately prior to use. In one embodiment, the adhesive, whencured, comprises from about 1% to about 95% (w/w) of non-volatilemoieties of Part A and from about 5% to about 99% (w/w) of non-volatilemoieties of Part B. In certain embodiments, Part A comprises PMDItogether with a catalyst. In certain other embodiments, part of thediphenylmethane 4,4′-diisocyanate, known as MMDI, present in the PMDI isrecovered by means of a suitable technological operation such asdistillation or crystallization.

The qualitative impact of the relative level of the water-insolubledispersible fraction on the performance characteristics of a two-partadhesive like those described herein is set forth in FIG. 4 (see alsoExample 18). It is understood that the amount of polypeptide composition(and the type of polypeptide composition) can be adjusted to optimizeproperties of the adhesive composition, e.g., viscosity, bond-strength,gap-filing capability, pot life, moisture resistance, and cost. Toillustrate, adhesive compositions formed from certain whey proteinderivatives have a short pot life, whereas adhesive compositions formedfrom certain castor protein have a longer pot life. To optimize theviscosity of the adhesive composition, the skilled artisan can adjustedthe amount of solid protein in the adhesive composition. For example,higher levels of solid protein in the adhesive composition can providean adhesive composition having a higher viscosity. Such higher viscosityadhesive compositions can be used for gap filing applications. Tooptimize the moisture resistance of the adhesive, the skilled artisancan adjust the amount of water-insoluble/dispersible protein relative tothe amount of water-soluble protein used to form the adhesivecomposition. In certain instances, the adhesive compositions contain alarger percentage by weight of the water-insoluble/dispersible proteinthan to the amount of water-soluble protein.

Various components of the activatable multi-part adhesive systems caninclude, for example, a polypeptide containing compound; and anisocyanate reactive composition as a separate component. The isocyanatereactive component can optionally comprise a protein that containsresidual peptide linkages.

In certain embodiments, the multi-part system further comprises eitheran ethylene copolymer resin, a hydroxyl functionalized polymer, ormixtures thereof. Non limiting examples of suitable ethylene copolymerresins include ethylene vinyl acetate (EVA),ethylene-co-vinylacetate-co-acrylic acid,ethylene-co-vinylacetate-co-methacrylic acid,ethylene-co-vinylacetate-co-vinylalcohol, carboxylated vinylacetate-ethylene copolymers, and ethylene vinyl alcohol (EVOH) resins.Non-limiting examples of hydroxyl functionalized polymers include watersoluble or partially water soluble polymers such as polyvinylalcohol,polyvinylbutyral-co-vinylalcohol, polyvinylacetate-co-vinylalcohol andthe like; and carbohydrates such as carboxymethylcellulose,ethylmethylcellulose, etc.

The ethylene copolymer can be used as a water dispersion (i.e., an EVAlatex). The dispersion can be a polymer latex containing a carboxylatedvinyl acetate-ethylene terpolymer stabilized with poly-(vinyl alcohol),commercially known as AIRFLEX 426® from Air Products, Inc. (63% solidsby weight). The ethylene copolymer can be used at a level of from 5% to50% by weight, from 10% to 40% by weight, or from 15% or 30% by weightof the total isocyanate reactive component (the level of ethylenecopolymer is expressed on a solids basis, and does not include the levelof water in the latex).

It is understood that the isocyanate reactive compositions (Part-B) of atwo-part adhesive kit can contain other optional ingredients, includinghydroxy-functional compounds (examples including amine-functionalcompounds, e.g., urea, and including polyols such as polyethyleneglycol, glycerin, polypropylene glycol, carbohydrates, starches,polyvinyl alcohol and copolymers thereof, trimethylolpropane, branchedpolyols such as trimethylolpropane ethoxylate, aromatic alcohols orpolyols, pentaerythritol and its polyol adducts, etc.). These types ofoptional hydroxy-functional compounds can either be blended togetherwith the proteins and the other ingredients during the preparation ofthe Part-B component, or they can be optionally added to the proteinsthemselves during or after any of the process steps that are used toprepare and isolate the proteins (e.g., during protein isolation orextraction from meal, during digestion, during derivatization, etc; orafter spray drying, after freeze drying, after isolation of awater-based paste of water-insoluble/dispersible protein, etc.). Whenthe optional hydroxyl-functional compounds are used in this way, thepreferred range of addition spans from about 0.1% to 10% by weight ofthe protein, and more preferably, from about 0.5% to 2% by weight of theprotein.

In certain embodiments, the isocyanate reactive composition furthercomprises water. In certain embodiments, the water is present in anamount ranging from about 30% to 75% (wt/wt), about 40% to 70% (wt/wt),or about 50% to 60% (wt/wt). In certain other embodiments, theisocyanate reactive composition further comprises from about 1% to 30%(wt/wt), about 10 to 30% (wt/wt), about 10% to 20% (wt/wt), about 1% to10% (wt/wt), or about 3% to 10% (wt/wt) polyol.

In embodiments where the isocyanate reactive composition comprises atleast 20% (wt/wt), 25%, or 27% (wt/wt) polypeptide. The polypeptide canbe an enzyme digested native protein, derivatized enzyme digestedprotein, or mixture thereof. In certain embodiments, the isocyanatereactive composition comprises derivatized enzyme digested protein. Incertain embodiments, the derivatized enzyme digested protein is at least50% (wt/wt), 60% (wt/wt), or 70% (wt/wt) of the polypeptide compositioncontained in the isocyanate reactive composition. In certainembodiments, the polypeptides contained in the isocyanate reactivecomposition are obtained from the same native protein source, or fromdifferent native protein sources. In certain embodiments, the isocyanatereactive composition remains a liquid and homogeneous upon storage orprocessing.

In another embodiment, a multi-part is created by mixing two or moreliquid streams, which are stable by themselves, and convert quickly intoa cured polymer under relatively mild conditions (relative to one-partadhesive systems). The two-part adhesives can cure by standing atambient conditions, or can be cured by exposure to heat, pressure, orboth.

It is understood that, for certain applications, the adhesivecompositions, in addition to containing a water-insoluble proteinfraction can also include a water-soluble polypeptide fraction.Depending upon the composition of the adhesive, the ratio of thewater-soluble polypeptide fraction to the water-insoluble polypeptidefraction ranges from 0:1 to 3:2 (w/w). Alternatively, the weight ratioof the water-insoluble polypeptide fraction to the water-solublepolypeptide fraction can be at least 1:1.

With regard to the two-part adhesives, the percent of solids in Part Bcan range from about 5% to about 30%, from about 8% to about 20%, orfrom about 10% to about 20% by weight of solids. Furthermore, dependingupon the application, the weight ratio of solids in Part B to theprepolymer can range from 100:0.1 to 0.1:100, from 50:1 to 1:50, from20:1 to about 1:20 or from 10:1 to about 1:10.

A variety of two-part adhesives are described in Examples 10-19.

General Considerations

It is understood that varying the reaction between the polypeptidecompositions and the reactive prepolymers can be done to optimizestability, shelf life, viscosity, and bonding performance that isnecessary for the final application.

In certain embodiments, the viscosity of all the types of polyisocyanatecompositions as described herein, is no more than (NMT) 50,000 cps, NMT25,000 cps, NMT 10,000 cps, or NMT 5,000 cps as measured at 25° C. untilthe polyisocyanate composition is cured.

Furthermore, the viscosity of the adhesive can be designed with aparticular application in mind. In one embodiment, where gap fillingadhesives are required, the minimum viscosity of the adhesive(polyisocyanate composition) should be no less than (NLT) 2000 cps, 3000cps, or NLT 4000 cps, as measured at 25° C. The viscosity of thepolyisocyanate compositions can be optimized by adjusting the level ofisolated and fractionated polypeptide described herein and/or theconditions used for preparing the composition. Typical conditions are inthe range from 25 to 100° C. at ambient pressure, with agitation of themixture until a sufficiently homogeneous composition is achieved.

Certain of the adhesives described herein are liquids having viscositieslow enough to render them pourable, sprayable, or curtain-coatable.Alternatively, certain of the adhesives described herein arenon-pourable, extrudable, spreadable gels or pastes. Non-pourable,extrudable, spreadable gels, or pastes may become pourable, sprayable,or curtain-coatable liquids at elevated temperature, and may optionallyrevert to non-pourable, extrudable or spreadable gels or pastes uponcooling.

In certain other embodiments, the polypeptide containing adhesivesdescribed herein are liquids, gels, or pastes stable enough to be storedfor at least one week, at least two weeks, at least one month, or atleast three months at ambient temperature (25° C.), and protected frommoisture. The term “stable” in connection with the viscosity of thepolyisocyanate composition refers to a viscosity that does not increaseby more than 10%, 25%, or 30%, from its initial value.

In addition, the polypeptide composition and the adhesive compositioncan be designed to have a polydispersity index. The term “polydispersityindex” refers to the ratio between the weight average molecular weightM_(w) and the number average molecular weight

${\overset{\_}{M_{n}}\text{:}\mspace{14mu}{PDI}} = \frac{\overset{\_}{M_{w}}}{\overset{\_}{M_{n}}}$

The terms “number average molecular weight,” denoted by the symbol Mnand “weight average molecular weight,” denoted by the symbol Mw, areused in accordance with their conventional definitions as can be foundin the open literature. The weight average molecular weight and numberaverage molecular weight can be determined using analytical proceduresdescribed in the art, e.g., chromatography techniques, sedimentationtechniques, light scattering techniques, solution viscosity techniques,functional group analysis techniques, and mass spectroscopy techniques(e.g., MALDI mass spectroscopy). For instance, as illustrated in Example28, average molecular weight and number average molecular weight of thepolypeptide composition was determined by MALDI mass spectroscopy.

Further, it is contemplated that polypeptide compositions havingdifferent molecular weights may provide adhesive compositions havingdifferent properties. As such, the weight average molecular weight,number average molecular weight, and polydispersity index can be animportant indicator when optimizing the features of the adhesivecomposition. In particular, it is contemplated that the ability tooptimize the molecular weight characteristics of the polypeptidecompositions provides advantages when preparing an adhesive compositionfor a particular use. Further advantages include obtaining adhesivecompositions with similar properties even though the polypeptidecomposition may be obtained from a different source (e.g., soy vs.castor) or when similar protein sources are harvested during differentseasons, over varying periods of time, or from different parts of theworld. For example, proteins isolated from soy and castor (each havingdifferent molecular weight distributions) can be made to have similarmolecular weight distributions through digestion and fractionationprocesses described herein (see Example 28). Accordingly, the ability tomeasure and control the consistency of molecular weight distributions iscontemplated to be beneficial when optimizing various features of theadhesive composition, e.g., long-term reproducibility of physicalproperties and process characteristics of formulated adhesives. Themolecular weight characteristics of the polypeptide composition can bealtered by subjecting the proteins therein to enzymatic digestion orfractionation according to the procedures described herein.

In certain embodiments, the PDI of the adhesives provided herein is fromabout 1 to about 3, from 1 to 1.5, from 1.5 to 2, from 2 to 2.5, from2.5 to 3, from 1 to 2, from 1.5 to 2.5, or from 2 to 3.

Furthermore, a moisture-resistant adhesive can be prepared by using thewater-insoluble/water dispersible extract alone, or optionally includinga plasticizer (for example, a water insoluble plasticizer), anorganosilane, and/or together with a lower-T_(g) polymer. The term“plasticizer” refers to any substance capable of increasing the freevolume (i.e. the molecular volume not occupied by the polypeptidemolecules or their bonds) of the water-insoluble/dispersible extract.The term “Tg” refers to the glass transition temperature of the polymer,i.e., the temperature at which free volume of the polymer is largeenough to allow translational relaxation and self diffusion of theminimal critical segment length of the polymer or molecule. In addition,moisture resistance can be imparted by means of crosslinking using abroad variety of crosslinking agents, for example, amine compounds,organosilane compounds, epoxy compounds, or epichlorhydrin-typematerials. A moisture-resistant pressure-sensitive adhesive can beprepared by using the water-insoluble/water dispersible extract blendedin combination with a plasticizer, optionally together with a low-T_(g)polymer or a high-Tg polymer.

Furthermore, the tack or bond strength of the pressure sensitiveadhesives (PSA) can be controlled through a number of means, such asshifting the glass transition (T_(g)) to higher or lower temperatures(by controlling the levels of monomeric and/or polymeric plasticizers)or incorporating flatting agents such as silicas, glass spheres, clays,and the like; by adjusting the crosslink density to higher or lowerlevels; by increasing or decreasing the plasticizer concentration; byblending with higher or lower molecular weight polymers; or by employingsome combination of these techniques.

It is understood that when evaluating the tack or bond strength of acomposite formed using an adhesive, the maximum achievable strength ofthe composite is dictated by the cohesive strength of the wood itself.To illustrate, if the adhesive is cohesively stronger than the wood,then wood failure will be the outcome. Further, it is contemplated thatthe adhesive composition may be tailored to provide a bond strengthappropriate for particular applications by selecting particularpolypeptide fractions, prepolymers, catalysts, and/or other additives.For example, an adhesive composition containing a DMDEE catalystprovided superior bond strength in one application (see Example 6).

Depending upon the application, the resulting adhesives may comprisefrom about 20% to about 80%, from about 30% to about 70%, from about 40%to about 60% (w/w) of prepolymer in the total adhesive (binder)composition.

Furthermore, depending upon the application, the resulting cured articlecan comprise from about 0.05% to about 5.0%, from about 0.1% to about4.0%, from about 0.2% to about 3.0%, from about 0.3% to about 2.0% (w/w)of prepolymer. In certain embodiments, the cured article can comprisefrom about 0.05% to about 2.5% (w/w) of prepolymer.

Furthermore, an article fabricated from one or more of the adhesivesdescribed herein can contain from about 1% to about 15%, or from about2% to about 10%, or from about 3% to about 8%, or from about 4% to about7%, or from about 3% to about 6% (w/w) of binder (adhesive) per curedarticle. In certain embodiments, the article fabricated from theadhesive may contain greater than 5% (w/w) of binder per cured article.In certain other embodiments, the article comprises from about 1.5% toabout 2.5% of binder per cured article.

Composite materials can contain from about 5% to about 85% (w/w), about15% to about 75% (w/w), about 30% to about 65% (w/w), about 1% to about10%, about 10% to about 20%, or about 20% to about 70% (w/w) binder.Laminate materials can contain from about 0.1% to about 10% (w/w), about0.5% to about 5%, about 1% to about 3% (w/w), about 1% to about 10%,about 20% to about 30%, or about 30% to about 70% (w/w) binder.

In certain embodiments, the adhesives described herein can be used inthe manufacture of particle board. With regard to the preparation ofmoisture-resistant cured particle board composites, the composites cancomprise a total binder level ranging from about 2.5% to about 4.5%(w/w) of the cured composite, wherein the binder includes awater-insoluble/water dispersible polypeptide fraction or awater-insoluble/water dispersible polypeptide-containing fraction and aPMDI fraction with an optional catalyst. The amount of PMDI can rangefrom about 30% to about 70% by weight of the cured binder, and the PMDIfraction can comprise between from about 1.3% to about 2.3% (w/w) of thecured composite (see Example 30).

In another embodiment, a moisture resistant composites can be preparedwith a total binder level ranging from about 1.5% to about 2.5% (w/w) ofthe cured composite, wherein the binder includes awater-insoluble/dispersible polypeptide fraction or awater-insoluble/dispersible polypeptide-containing fraction and a PMDIfraction with an optional catalyst, The PMDI fraction can comprises fromabout 0.3% to about 1.4% (w/w) of the cured composite (see Example 31).

In another embodiment, a moisture-resistant cured particle boardcomposite can be prepared containing a total binder level ranging fromabout 2.5% to about 3.1% by weight of the cured composite, wherein thebinder comprises a water-insoluble/water dispersible polypeptidefraction or a water-insoluble/water dispersible polypeptide-containingfraction, an optional polymer latex fraction, and a PMDI fraction withoptional catalyst. The PMDI comprises from about 5% to about 65% byweight of the cured binder and from about 0.3% to about 2% by weight ofthe cured composite. The optional polymer latex is an EVA latex polymercomprising from about 0% to about 45% by weight of the cured binder andfrom about 0% to about 1.2% by weight of the cured composite (seeExample 32).

In another embodiment, a moisture-resistant cured particle boardcomposite can be prepared with a total binder level ranging from about1.2% to about 2.5% by weight of the cured composite. The bindercomprises a water-insoluble/water dispersible polypeptide fraction or awater-insoluble/water dispersible polypeptide-containing fraction, anoptional polymer latex fraction, and a PMDI fraction with optionalcatalyst. The PMDI fraction comprises from about 0.1% to about 1.1% byweight of the cured composite (see Example 32).

In the event that moisture-resistance is not a requirement for theend-use application, cured composites can also be prepared with a totalbinder level of less than approximately 5% by weight of the curedcomposite, wherein the binder comprises a water-insoluble/waterdispersible polypeptide fraction or a water-insoluble/dispersiblepolypeptide fraction and a PMDI fraction with an optional catalyst. ThePMDI fraction can comprise from about 0.05% to about 2.5% (w/w) of thecured composite. Depending upon the level of water that can be toleratedduring the manufacture of the composite, binder levels of greater than5% can also be employed, wherein the PMDI fraction comprises at least0.05% by weight of the cured composite.

With regard to the two-part adhesives, the level of water that can beused to disperse the ingredients and to fabricate a composite can beadjusted for the specific application by virtue of controlling the %solids in the Part-B component, the weight ratio of the Part-B solidsingredients to PMDI, and the total binder level in the finishedcomposite (on a solids basis). Depending on the level of water that isrequired to fabricate the composite, the % solids in the Part-Bcomponent will preferably range from approximately 5% to 30% by weightsolids, and more preferably from about 9% to about 20% by weight solids.Similarly, the Part-B solids to PMDI weight ratio preferably ranges fromapproximately 20:1 to 1:20, and more preferably from about 10:1 to 1:10.The total percentage of binder in the cured composite (on a solidsbasis) preferably ranges from approximately 1% to 15% by weight of thecured composite, and more preferably from about 2% to 10% by weight.

Similar formulation considerations apply to the fabrication andmanufacture of plywood composites. For example, moisture-resistant curedplywood assemblies can be laminated with bondline adhesive levelsranging from approximately 0.008 pounds/ft.² up to approximately 0.056pounds/ft.², wherein the adhesive includes a water-insoluble/dispersiblepolypeptide-fraction or a water-insoluble/dispersiblepolypeptide-containing fraction, an optional polymer latex fraction, anda PMDI fraction with an optional catalyst. The PMDI can comprise fromabout 20% to about 70% (w/w) of the cured adhesive. The optional polymerlatex can be an EVA polymer latex comprising between about 0% and 45% ofthe cured binder. It is contemplated that plywood composites preparedwith these types of adhesive compositions will be capable ofwithstanding boiling water and hence will be extremely moistureresistant.

In the event that moisture-resistance is not a requirement for theend-use application, cured plywood composites can also be prepared withbondline adhesive levels of less than approximately 0.056 pounds/ft.²,wherein the adhesive includes a water-insoluble/dispersible polypeptidefraction or a water-insoluble/dispersible polypeptide-containingfraction and a PMDI fraction with an optional catalyst. The PMDIfraction comprises less than approximately 20% by weight of the curedadhesive.

The level of water that may be used to disperse the ingredients and tofabricate a plywood composite can be adjusted for the specificapplication by virtue of controlling the % solids in the Part-Bcomponent, the weight ratio of the Part-B solids ingredients to PMDI,and the total bondline application level in the finished composite (on asolids basis). Depending on the level of water that is required tofabricate the composite, the % solids in the Part-B component willpreferably range from approximately 5% to 30% by weight solids, and morepreferably from about 8% to 20% by weight solids. Similarly, the Part-Bsolids to PMDI weight ratio preferably ranges from approximately 20:1 to1:20, and more preferably from about 10:1 to 1:10.

In certain embodiments, both the one-part, the two-part and themulti-part type adhesives are cold curable. In certain embodiments, theadhesives include a cure catalyst (for example, DMDEE in the case ofadhesives containing a polyisocyanate) that facilitates curing in theabsence of applied heat. In certain embodiments, the adhesives (forexample, the polyisocyanate containing adhesives) are cured in thepresence of moisture at a temperature of about 10° C. to about theambient temperature range (25° C., to as high as 30° C.). In certainother embodiments, the cold cure temperature ranges from 20° C. to 27°C. In other embodiments, the adhesives are hot cured, at temperaturesgreater than 30° C. Hot curing may at temperatures in the range from 50°C. to 300° C., or from 90° C. to 275° C., or from 110° C. to 250° C.

V. Applications of Adhesive Compositions

The adhesive compositions described herein can be used in a variety ofdifferent applications, which include, for example, bonding togethermany different types of substrates and/or creating composite materials.

Accordingly, the invention provides a method of bonding a first articleto a second article. The method comprises the steps of (a) depositing ona surface of the first article any one of the foregoing adhesivecompositions thereby to create a binding area; and (b) contacting thebinding surface with a surface of the second article thereby to bond thefirst surface to the second surface. The method optionally alsocomprises the step of, after step (b), permitting the adhesivecomposition to cure, which can be facilitated by the application ofpressure, heat or both pressure and heat.

The adhesive compositions can be applied to the surfaces of substratesin any conventional manner. Alternatively, the surfaces can be coatedwith the composition by spraying, or brushing, doctor blading, wiping,dipping, pouring, ribbon coating, combinations of these differentmethods, and the like. Many of the Examples describe bonding twoarticles together. In addition, Example 23 describes the production oflaminates using the adhesives described herein.

The invention also provides a method of producing a composite material.The method comprises the steps of (a) combining a first article and asecond article with any one of the foregoing adhesive compositions toproduce a mixture; and (b) curing the mixture produced by step (a) toproduce the composite material. The curing can comprise applyingpressure, heat or both pressure and heat to the mixture.

The terms “substrate”, “adherend” and “article” are interchangeable andrefer to the substances being joined, bonded together, or adhered usingthe methods and compositions described herein. In certain embodiments,the first article, the second article or both the first and secondarticles are lignocellulosic materials, or composite materialscontaining lignocellulosic material. Furthermore, the first article, thesecond article or both the first and second articles can comprise ametal, a resin, a ceramic, a polymer, a glass or a combination thereof.It is understood that the first article, the second article, or both thefirst article and the second article can be a composite.

The compositions can be used to bond multiple lignocellulosic materials(adherends) together to prepare composite wood products. Furthermore, itis understood that at least one of the adherends bonded together and/orincluded in the composite can be wood, wood fiber, paper, rice hulls,fiberglass, ceramic, ceramic powder, plastic (for example, thermosetplastic), cement, stone, cloth, glass, metal, corn husks, bagasse, nutshells, polymeric foam films or sheets, polymeric foams, fibrousmaterials, or combinations thereof.

The amount of adhesive composition applied to the adhesive bond betweensubstrates may vary considerably from one end use application, or typeof adhesive used, or type of substrate, to the next. The amount ofadhesive should be sufficient to achieve the desired bond strength andbond durability under a given set of test conditions.

The amount of an adhesive composition applied may be in the range offrom about 5 to about 50 grams per square foot, from about 8 to about 60grams per square foot, from about 10 to about 30 grams per square foot,from about 20 to about 50 grams per square foot, from about 15 to about40 grams per square foot, of bond surface area (i.e., the bond surfacearea being the area of overlap between the substrates to be bonded bythe adhesive composition).

The adhesive compositions can be used to fabricate multi-substratecomposites or laminates, particularly those comprising lignocellulosicor cellulosic materials, such as wood or paper. The adhesives can beused to prepare products such as plywood, laminated veneer lumber (LVL),waferboard (also known as chipboard or OSB), particleboard, fiberboard,fiberglass, composite wooden I-beams (I-joists), and the like. Themanufacture of fiberglass using the adhesives described herein isdescribed in more detail in Example 36.

The adhesive compositions can also be used to fabricate compositematerials, which include, for example, chip board, particle board, fiberboard, plywood, laminated veneer lumber, glulam, laminated whole lumber,laminated composite lumber, composite wooden I-beams, medium densityfiberboard, high density fiberboard, extruded wood, or fiberglass. Thecomposite can be a thermosetting composite or a thermoplastic composite.The manufacture of particle board using the adhesives described here isdescribed in more detail in Examples 24 and 30-32. The manufacture ofplywood using the adhesives described herein is described in Example 23.

In certain embodiments where two-part adhesives are used, Part-A and/orPart-B can be premixed with cellulosic components such as wood fiber,sawdust, or other components, and then mixed together and permitted tocured to create a composite material. Alternatively, Parts A and B canbe mixed together before or during the addition of cellulosiccomponents. The resulting mixture is then permitted to cure to create acomposite material. Mixing can be accomplished using conventional mixerssuch as paddle mixers, static mixers and the like, currently known inthe art.

Premixed components can be added to a sawdust cellulosic component viaspraying application or dripping application, followed by rigorousmixing. Alternatively, each adhesive component can be added to thesawdust sequentially (“sequential addition”), simultaneously, in tandem(“tandem addition”) without premixing, and then the mixture isrigorously blended. Blending can be achieved via any conventional mixingprocess including high speed paddle mixing (e.g., with a Littlefordblender or a Henchel-type mixer), sigma-blade mixing, ribbon blending,etc. Additional materials can also blended concurrently or sequentiallywith the mixture including fillers such as calcium carbonate,aluminosilicates, clays fumed silica, nano-sized inorganic particulates,latex polymers, or antimicrobial compounds, etc.

Viscosity, sprayability, and/or spreadability of the adhesive componentscan be controlled by adjusting the amount of water added to the Part-Bcomponent before it is premixed with Part-A, or by adding water afterthe two components have been premixed. When premixing is not employed(e.g., if tandem or sequential mixing is employed), water can be addedto the mixture as needed for the purpose of influencing viscosity andsawdust-particle surface coverage.

In another approach, for a two-part adhesive, Part-A and/or Part-B canbe mixed together along with cellulosic components such as wood fiber,sawdust, or other components; blended with optional polymeric components(e.g., virgin or recycled) plasticizers, stabilizers, and otheradditives in liquid, pelletized, or powdered form; and then extruded viasingle screw or twin screw extrusion methods to create cured compositeproducts such as rail ties, fencing posts, fining strips, decking, etc.The extrudate can be used to feed an injection molding machine for thepurpose of fabricating molded parts such as garage door panels, car doorpanels, cabinet doors, toilet seats, and the like.

Under certain circumstances, pressure and/or heat can be used tofacilitate curing. The amount of pressure and the time period for whichthe pressure is applied are not limited and specific pressures and timeswill be evident to one skilled in the art from the present disclosure(see the various Examples). In certain embodiments, a pressure ofapproximately 10 to 250 psi is applied from about 10 minutes to about 2hours, or from about 10 minutes to about 30 minutes (depending on thetemperature). The pressure, heating, or application of both pressure andheat decreases the viscosity of the polypeptide-containing adhesivesdescribed herein, facilitating their flow in the contact area, such thata bonding region is created whereby there is a continuum between theadherends. The amount of pressure, heat time or their combination can beoptimized to ensure such continuum and will depend on the adherends'physical or chemical properties as well as on the rate of the adhesive'sviscosity-build throughout the cure cycle.

Depending upon the adhesive used, the resulting article can be moistureresistant. Furthermore, the article may remain intact after boiling inwater for 5 minutes, 10 minutes, 30 minutes, 1 hour, 2 hours, or 3hours. Furthermore, two or more components of the article may remainbonded after boiling in water for 5 minutes, 10 minutes, 30 minutes, 1hour, 2 hours or 3 hours. Furthermore, the article when boiled in waterfor 5 minutes, 10 minutes or 30 minutes, may display less than a 20%increase, or less than a 10% increase in volume relative to the articleprior to exposure to the water.

Furthermore, when the article (for example, a composite material, alaminate, or a laminate containing a composite material) contains alignocellulosic material, the article exhibits no less than 75% cohesivefailure of the lignocellulosic component when the article is placedunder a loading stress sufficient to break the article. In certainembodiments, when an article (resulting product) contains alignocellulosic material, the article has a block shear strength asmeasured under the D905 and D2559 ASTM standards of greater than 3,000lbs., 4,000 lbs., 5,000 lbs. or 6,000 lbs.

Throughout the description, where compositions and articles aredescribed as having, including, or comprising specific components, orwhere processes and methods are described as having, including, orcomprising specific steps, it is contemplated that, additionally, thereare compositions and articles of the present invention that consistessentially of, or consist of, the recited components, and that thereare processes and methods according to the present invention thatconsist essentially of, or consist of, the recited processing steps.

Practice of the invention will be more fully understood from theforegoing examples, which are presented herein for illustrative purposesonly, and should not be construed as limiting the invention in any way.

EXAMPLES Example 1: One-Part Adhesive Comprising Polymeric Isocyanate,Polyol, and a Polypeptide Composition Derived from Whey

Digested whey protein (lot 5-72, referred to herein as digested wheyprotein pH 6.5) was obtained as an experimental sample from Prof. S.Braun, the Laboratory of Applied Biology at the Hebrew University ofJerusalem, Israel, and was prepared as follows; Whey protein (WPI-95®Whey Protein Isolate; Nutritteck, 24 Seguin Street, Rigaud, QC, CanadaJ0P 1P0) was suspended in water at a ratio of 1:6 (w/w). The pH of thesuspension was adjusted to pH 7 with 5N NaOH, and was heated to 55° C.while stirring. FLAVOURZYME 500 MG® (from NOVOZYMES') then was added ata ratio of 20 g per kg of whey protein, and the mixture was stirred atthe same temperature for 4 hours. The resulting aqueous mixture was pH6.5. The resulting mixture then was spray-dried to yield digested wheyprotein as a pale yellow powder.

A prepolymer (JM30-1) was prepared by reacting 73.81 parts of apolymeric MDI (PMDI), RUBINATE-M isocyanate from Huntsman Corp., with16.19 parts of a polyoxypropylene glycol of 2000 molecular weight(JEFFOL PPG-2000 polyol from Huntsman Corp.), and with 10 parts of adigested and dried whey protein (weight basis).

The prepolymer ingredients were mixed together simultaneously in aone-step process under a nitrogen atmosphere at a temperature of 95° C.,and were allowed to react for 2 hours. The resulting homogeneoussolution then was allowed to cool to 25° C. under static ambientconditions. Upon cooling, phase separation was observed. A loosesediment settled to the bottom of the glass container and a cloudysupernatant remained on top. The sediment was readily redispersed withstirring, under nitrogen. The resulting prepolymer (a viscous liquiddispersion) then was used to prepare a series of one-partmoisture-curable and thermally-curable adhesives with different catalysttypes and catalyst levels. The catalysts included iron acetylacetonate(Fe(III) 2,4-pentanedionate (FeAcAc), CAS Number 14024-18-1, obtainedfrom Alfa Aesar Inc.), and a morpholine derivative (JEFFCAT DMDEEcatalyst from Huntsman Corp.).

Each sample was prepared by mixing the catalysts with the prepolymerunder nitrogen, and by then heating the mixtures in sealed containers ina gravity oven at a temperature of 80° C. for approximately 1.5 hours(with periodic removal for shaking by hand). Upon heating, the dispersedcomponents were observed to become soluble as evidenced by the improvedclarity of the solutions. Upon cooling (after the samples were removedfrom the oven), the solutions became cloudy, but they remained stablewith no settling even after several weeks of prolonged storage underambient conditions (25° C.). The compositions of the adhesives are givenin Table 2.

TABLE 2 Adhesive Compositions and Bond Strengths Bond Strength Catalysttype and level (peak load at failure) Sample (phr)* in pounds (+/−S.D.)1-17A 0.5 phr DMDEE + 4990 (+/−780)  0.1 phr FeAcAc 1-17B 0.5 phr DMDEE5510 (+/−750)  1-17C 0.35 phr DMDEE 5400 (+/−1070) 1-17D 0.2 phr DMDEE5800 (+/−1160) 1-17E 0.1 phr FeAcAc 3230 (+/−1090) *“phr” refers to thenumber of parts of a particular substance per one hundred parts adhesive

The bond strength of the one-part adhesives to Lodgepole Pine (moisturecontent approximately 10%) was evaluated via a compressive shear test(ASTM D905), which is also described in ASTM D2559. 2″×2″×¾″surface-sanded blocks were separated into pairs, and werepre-conditioned for 24 hours under ambient laboratory conditions (23°C., at approximately 45% RH). Each of the adhesives in Table 2 was usedto coat the inner surface of matched wood block pairs (replicates of 6pairs per adhesive). 0.4 to 0.6 g of each adhesive was applied with aplastic pipette and was spread with a spatula onto a 2″×1¾″ section of atreated-face (only one block per pair was coated with adhesive). Theadhesive-coated surface then was sandwiched with the secondtreated-block of the pair, so that the treated surfaces were in contactwith the adhesive over a 2″×1¾″ contact area. This allowed ¼″ of eachblock to overhang in a “lap-shear” type geometry, similar to thatdescribed in ASTM D2559. The sandwiched specimens then were cured underpressure (214 psi) for 30 minutes using a Carver press with platentemperatures set at 200° C. During the assembly of the samples (prior totheir exposure to the press cycle), the adhesives that were preparedwith the DMDEE catalyst were observed to foam when exposed to the woodsurfaces. The samples prepared with the Fe catalyst alone remaineduncured (no foaming) until after the press cycle. After pressing, all ofthe adhesives were cured as evidenced by the rigid foam-likecharacteristics of the excess material that was squeezed out from thebondline area. The average compressive shear bond strength of eachsample set is also given in Table 2.

The results illustrate that high bond strengths to wood can be achievedusing adhesives containing isocyanate compounds and whey proteinderivatives. Moreover, the catalyst choices can include those that favorlong staging times under ambient conditions (long open times) such asFeAcAc, those that favor more rapid moisture cure such as DMDEE, andmixtures thereof. Adhesives with FeAcAc require thermal activation,whereas those made with DMDEE can be cold cured under ambientconditions. Thus, a wide variety of one-part adhesives can be formulatedto meet the needs of a variety of end-use processes and applications.

In order to assess the reproducibility of these procedures, twoadditional sets of specimens (6 block shear specimens per set) wereprepared using a freshly prepared mixture of the 17-1E adhesive. Theaverage block shear strengths for the two sets were determined to be3,660 pounds (+/− 930), and 3,570 pounds (+/− 850), respectively. Thepooled average and standard deviation of the three data sets (n=18) wasdetermined to be 3480+/− 920 pounds.

Example 2: One-Part Adhesive Comprising Polymeric Isocyanate and aProtein Derived from Whey

The procedures for prepolymer preparation, adhesive preparation, andblock-shear sample preparation were identical to those reported inExample 1.

A prepolymer was prepared (JM39-1) using the same PMDI and the samedigested whey protein (pH 6.5). This prepolymer was analogous to theprepolymer used in Example 1 (JM30-1) with one exception: the polyolcomponent was omitted and was replaced with an equivalent level of thesame digested whey protein. The final composition was approximately75/25 (w/w) PMDI/protein. An adhesive (54-1) then was made with 0.1 phrFeAcAc to determine the effect of the presence or absence of polyol onbond strength. The average block-shear bond strength of Lodgepole Pinesamples made with the 54-1 adhesive was determined to be approximately3,700 pounds (+/− 980). This result was very similar to that obtainedfor the analogous adhesive in Example 1 which contained a polyolcomponent (1-17E). This result shows that the use of a polyol in a1-part adhesive is optional, and that the choice of whether or not toemploy a polyol component in the adhesive depends on end-useperformance. As will be shown in subsequent Examples, this choice candepend on wood type, protein type, and other process-related attributessuch as viscosity, and dispersion stability.

A second prepolymer sample (JM26-3) was analogously made using aPMDI/protein ratio (w/w) of 87/13. An analogous adhesive was alsoprepared with 0.1 phr FeAcAc (52-1) and was tested with Lodgepole Pineto yield an average block shear strength of approximately 1,300 (+/−1300) pounds. Thus, although adhesives can be prepared with a broadrange of PMDI/protein ratios, the performance in terms of shear strengthcan be affected by the level of protein in the adhesive. In the presentexample, the adhesive bond strength to Lodgepole Pine was improved whenthe digested whey protein (pH 6.5) was used at ratios exceeding 13% byweight of the prepolymer. Prepolymers containing lower ratios ofPMDI/digested whey protein (pH 6.5) were also prepared (PMDI/proteinw/w<75/25). However, unlike JM39-1, these prepolymers were more viscousand could not be as easily mixed or poured under ambient conditions.Such materials conceivably can be used to make adhesives (e.g.,caulkable adhesives and sealants). However, if pourable adhesives aredesirable (low enough in viscosity to be pourable at 25° C.), thedigested whey protein level should be less than 25% by weight of theprepolymer. Higher levels of protein can still be used to achievepourable adhesives if either a reactive or non-reactive diluent isformulated with the adhesive to lower its viscosity.

Example 3: Effect of pH on the Reactivity of Digested Whey Protein

A prepolymer sample was made having the same PMDI/protein ratio assample JM39-1 from Example 2 (approximately 75/25 PMDI/protein) usingthe same synthetic methods as outlined in Example 1. However, in thisexample, a different type of digested whey protein was employed.

The protein derivative was obtained as an experimental sample (lot 5-80,referred to herein as digested whey protein pH 3.5) from the Laboratoryof Applied Biology at the Hebrew University of Jerusalem, Israel, andwas prepared as follows. Whey protein (WPI-95® Whey Protein Isolate;Nutritteck, 24 Seguin Street, Rigaud, QC, Canada J0P 1P0) was suspendedin water at the ratio of 1:6 (w/w). The pH of the suspension wasadjusted to pH 7 with 5N NaOH. Flavourzyme 500 MG® (NOVOZYMES') was thenadded at a ratio of 20 g per kg of whey protein, and the mixture wasstirred at ambient temperature for 18 hours. The pH of the resultingmixture was then lowered by the addition of concentrated HCl to pH 3.5,and it was spray-dried to yield a pale yellow powder.

During the synthesis of the prepolymer, significant foaming wasobserved, and the resulting product became a thermoset solid. Thus,unlike the digested whey protein (pH 6.5), the more acidic digestedprotein (pH 3.5) produced a rigid solid when it reacted with PMDI.Although such a material could find use in many applications (e.g., as a2-part reactive system for use as an adhesive, or as a 2-part reactioninjection molding system for use in fabricating molded thermosetmaterials), this result demonstrates that in order to prepare a pourable1-part adhesive with high levels of the digested whey protein, it ispreferred that the digested whey protein be prepared under near-neutralconditions.

Example 4: One-Part Adhesive Comprising Polymeric Isocyanate and aProtein Derived from Whey: Southern Yellow Pine (SYP) vs. Lodgepole Pine

In a subsequent test, the 54-1 adhesive from Example 2 was used toprepare block shear samples with southern yellow pine (SYP) rather thanLodgepole Pine. The wood was planed, cut to size, and sanded as noted inExample 1. In addition, the SYP was conditioned at 21° C. and 65%relative humidity for at least 24 hours in an environmental chamber toachieve a moisture content in the wood of approximately 12%. Block shearsamples were assembled using procedures as outlined in Example 1. Sixblock-shear pairs then were cured under pressure (250 psi) for 30minutes using a Carver press with platen temperatures set at 205° C. Thesamples were tested for average compressive shear strength as outlinedin Example 1.

The average compressive shear strength (peak load) at failure for theSYP specimens was determined to be only 100 (+/− 45) pounds. Thus, thestrength of the joint with SYP was significantly less than that whichwas observed for the Lodgepole Pine specimens that were tested inExample 2 (3,700 pounds). Thus, although the specific protein in thisexample (digested whey, pH 6.5) can be used to formulate strongadhesives, the bond strength as illustrated here has the potential tovary according to the type of wood that is employed as the adherend.

Example 5: Testing of SYP with One-Part Adhesives Comprising PolymericIsocyanate and Various Proteins Derived from Whey

The protein derivatives in this Example included digested whey pH 6.5(lot 5-72, see Example 1 for the digestion procedure), digested wheypH=3.5 (lot 5-80, see Example 3 for the digestion procedure), and athird protein derivative from whey (a digested and deaminated proteinfrom whey). The digested and deaminatined protein was produced byreacting the enzyme digested whey protein (pH 6.5), described above,with nitrous acid.

The specific digested and deaminated whey protein for this Example wasobtained as an experimental sample (lot 5-75) from Prof. S. Braun, theLaboratory of Applied Biology at the Hebrew University of Jerusalem,Israel, and was prepared as follows. Whey protein (WPI-95® Whey ProteinIsolate; Nutritteck, 24 Seguin Street, Rigaud, QC, Canada J0P 1P0) wassuspended in water at a ratio of 1:6 w/w. The pH of the suspension wasadjusted to pH 7 with 5N NaOH. Flavourzyme 500 MG® (NOVOZYMES') then wasadded at the ratio of 20 g per kg of whey protein, and the mixture wasstirred at ambient temperature for 18 hours. L-lactic acid (90%, 120 gper kg whey protein) then was added to bring the pH to 4.4 followed bygradual addition (over a 20 hour period) of sodium nitrite solution inwater (0.4 kg/1, 0.4 liter per kg whey protein) while stirring. Thereaction then was left to stand at ambient temperature for 40 hours.Na₂S₂O₅ (0.2 kg per kg whey protein) then was added; and then thereaction was heated to 60° C. and stirred for 15 minutes. After coolingto ambient temperature, the reaction was brought to pH 2.0 withconcentrated HCl. The reaction mixture was then left at 10° C. for 18hours and the precipitate was collected by centrifugation for 15 minutesat 24,000×g. The precipitate was re-suspended in 10 mm citric acid (3vol. per vol. precipitate), and then was collected and subsequentlyfreeze-dried to yield a pale yellow powder.

The adhesives in this Example were prepared by mixing the whey proteinderivatives with a premixed solution containing RUBINATE-M PMDI fromHuntsman Corp. and 0.1% FeAcAc by weight. The proteins were stirred intothe PMDI solution under ambient conditions while maintaining a blanketof nitrogen over the mix. The resulting dispersions then were used toprepare SYP block-shear specimens in accord with the procedures outlinedin Example 4. The compositions of the adhesives and the resultingaverage block shear strengths are given in Table 3.

TABLE 3 Adhesive Compositions and Average SYP Block Shear Strengths BondStrength Weight % (peak load at failure) Sample Protein Type Protein inpounds (+/−S.D.) 56-1 Flavourzyme digested 15 230 +/− 110 whey, pH 6.5(lot 5-72) 56-2 Flavourzyme digested 15 620 +/− 620 whey, pH 3.5 (lot5-80) 56-3 Washed digested and 15 5440 +/− 1260 deaminated whey protein(lot 5-75) 56-4 Flavourzyme digested 25 90 +/− 70 whey, pH 6.5 (lot5-72) 56-5 No protein 0 4500 +/− 760 

These results show that the strength of the adhesive is dependent on themethod that is used to prepare the protein derivatives. In fact, withthe exception of the digested and deaminated whey protein, the otherproteins actually had a deleterious effect on adhesion strength. Thus,when preparing a 1-part adhesive for SYP from whey-based proteins, thepreferred protein appears to be the digested and deaminated wheyprotein. A similar preference was observed for castor-based proteinsthat were synthesized via a 1-step reaction process (see Example 7).

Example 6: Testing of SYP with One-Part Adhesives Containing PolymericIsocyanate and Protein Derived from Castor

The adhesives in this Example contained 15 parts by weight of anEverlase digested protein from castor that was obtained as anexperimental sample (lot 5-83, referred to herein as “digested castor”)from Prof. S. Braun, the Laboratory of Applied Biology at the HebrewUniversity of Jerusalem, Israel. The digested castor was prepared asfollows.

Castor meal protein was suspended in water at the ratio of 1:10 w/w.Calcium chloride was added to the effective concentration of 10 mM, andthe pH of the suspension was adjusted to pH 9 by the addition of 10 NNaOH. The reaction was heated to 55° C. while stirring. Everlase 16LType EX® (NOVOZYMES') then was added at the ratio of 10 g per kg ofcastor meal protein, and the mixture was stirred at the same temperaturefor 4 hours. The resulting mixture then was brought to a pH 3.5 withcitric acid and was spray-dried to yield a tan powder.

The enzyme digested castor protein was mixed together with either (1) 85parts by weight of neat Rubinate-M PMDI; (2) 85 parts by weight of apremixed solution of Rubinate PMDI containing 0.1% FeAcAc, or (3) 85parts by weight of a 90/10 (w/w) PMDI/PPG2000 prepolymer that waspre-formulated with 0.1% FeAcAc (JM62-2). The JM62-2 prepolymer wassynthesized via the same procedures outlined in Example 1 for otherprepolymers.

The adhesives were prepared by hand-mixing aliquots of the protein intothe isocyanate-based solutions with a spatula under a blanket ofnitrogen at 23° C. The resulting dispersions then were sealed undernitrogen and were placed into a static gravity oven at a temperature of80° C. for a period of 2 hours. The dispersions were initiallycharacterized as having relatively low viscosities. Upon removal fromthe oven, there was evidence of foaming, and it was apparent that thedispersions had become more viscous. Upon opening the jars, the reactionproducts were observed to be viscous, but were still easily dispensableand could be readily spread with a spatula. The dispersions were alsoshelf-stable with no evidence of settling under ambient conditions afterseveral weeks of observation.

In certain cases, DMDEE catalyst was then added to the adhesives (i.e.,after the 2 hour period at 80° C.) at a concentration of 0.13 parts perhundred parts adhesive (phr). The adhesives were used to prepare SYPblock shear specimens in accord with the procedures outlined in Example4. The compositions of the adhesives and resulting average block shearstrengths are given in Table 4. In addition, the failed wood specimenswere analyzed for % wood failure in accord with the D905 and D2559 ASTMstandards.

TABLE 4 Adhesive Compositions and SYP Block Shear Strength ComparisonsAverage Bond Strength (peak Additional Average % load at failure ProteinType PMDI-based component Catalyst wood failure in pounds) Sample (15%by weight) (85% by weight) (phr) (+/−S.D.) (+/−S.D.) 61-2 EverlasePMDI + 0.1% FeAcAc 0  1 (1) 200 (80)  digested castor (lot 5-83) 62-1Everlase 90/10 (w/w) 0.13 DMDEE 97 (3) 6070 (380)  digested castorPMDI/PPG (lot 5-83) 2000 62-2 Everlase JM62-2 0  79 (17) 4710 (1050)digested castor 90/10 (w/w) PMDI/PPG (lot 5-83) 2000 + 0.1% FeAcAc 62-3Everlase JM62-2 0.13 DMDEE 100 (0)  6000 (1050) digested castor 90/10(w/w) PMDI/PPG (lot 5-83) 2000 + 0.1% FeAcAc 62-4 none JM62-2 0 98 (2)5800 (1600) 90/10 (w/w) PMDI/PPG 2000 + 0.1% FeAcAc

Sample 61-2 was observed to exhibit poor bond strength to SYP, much likethe 56-1 sample from Example 5. In both cases, the adhesives wereformulated with 85/15 (w/w) of PMDI/digested protein (derived from wheyin Example 5, and derived from castor in the present example). However,the bond strength was observed to improve dramatically when a fractionof the PMDI was replaced by a polyol (62-2), and even more so when anadditional catalyst was added (62-3). The performance also appeared todepend on the choice of catalyst, particularly when the adhesive wasformulated with protein. For example, sample 62-4 which contained noprotein, was noted to out-perform the protein-containing sample 62-2,even though both adhesives employed FeAcAc as a catalyst. Surprisingly,when DMDEE was added to the formulation, the strength of the adhesivebond was observed to exceed the cohesive strength of the wood itself,independent of whether the DMDEE was added in the presence of FeAcAc(62-3), or in the absence of FeAcAc (62-1).

These results demonstrate that high bond strengths to SYP can beachieved with isocyanate-based adhesives containing digested castorproteins, particularly when the adhesive contains a polyol componentwhich had been pre-reacted with PMDI prior to the addition of theprotein to the formula. Further enhancements can be achieved by varyingthe nature of the catalysts that are employed.

The attributes of these adhesives are potentially advantageous forcertain adhesive applications, particularly those that may require longstaging times prior to pressing, as is sometimes the case for laminatedveneer lumber (LVL) manufacturing processes. When staging times exceedseveral minutes, low-viscosity liquid adhesives may tend to bleed intothe wood veneers. This can sometimes lead to bond-line starvation, andto insufficient bond strength after pressing. Also, many one-partisocyanate systems are designed to cure with moisture, and hence maycure prematurely during staging periods. This can also lead to thedeterioration of final bond strength after pressing.

Adhesives like those developed in the present Example have the advantageof being high enough in viscosity to maintain a bond line for prolongedperiods of time without bleeding. In addition, premature reaction withmoisture can be conveniently avoided by one of several mechanismsincluding: (1) the omission of moisture-activated catalysts; (2) the useof thermally-activated catalysts; (3) the use of minimal amounts ofmoisture-activated catalysts together with thermally activatedcatalysts, and (4) the maintenance of a high enough viscosity duringstaging so as to mitigate moisture diffusion into the adhesive.

Example 7: One-Part Adhesives Containing Polymeric Isocyanate andProteins Derived from Castor: 1-Step vs. 2-Step Synthesis

Adhesives in this Example were prepared with the same digested castorprotein described in Example 6, and separately with another castorprotein derivative, digested and deaminated castor protein. Thisderivative was obtained as an experimental sample (lot 5-82) from Prof.S. Braun, the Laboratory of Applied Biology at the Hebrew University ofJerusalem, Israel. The digested and deaminated castor protein derivativewas produced by reacting the enzyme-digested castor protein, describedabove, with at least one member selected from the group consisting ofnitrous oxide, nitrous acid, and salts of nitrous acid.

The specific preparation procedure for the digested and deaminatedcastor protein that was used in this example (lot 5-82) was as follows.Castor meal protein was suspended in water at a ratio of 1:10 (w/w).Calcium chloride was added at an effective concentration of 10 mM, andthe pH of the suspension was adjusted to pH 9 by the addition of 10 NNaOH. The reaction was heated to 55° C. while stirring. Everlase 16LType EX® (NOVOZYMES') then was added at a ratio of 10 g per kg of castormeal protein, and the mixture was stirred at the same temperature for 4hours. L-lactic acid (90%, 120 g per kg castor protein) then was addedto bring the mixture to pH 4.4 followed by gradual addition (over a 20hour period) of sodium nitrite solution in water (0.4 kg/1, 0.4 literper kg castor protein) while stirring. The reaction then was left tostand at ambient temperature for 40 hours. Na₂S₂O₅ (0.2 kg per kg castorprotein) was then added, and the reaction was heated to 60° C. andstirred for 15 minutes. After cooling to ambient temperature, thereaction was brought to pH 2.0 with concentrated HCl. It was then leftat 10° C. for 18 hours, and the resulting precipitate was separated bycentrifugation for 15 minutes at 24,000×g. The precipitate wasre-suspended in 10 mM citric acid (3 vol. per vol. precipitate), andthen it was collected and subsequently freeze-dried to yield a tanpowder.

For comparative purposes, adhesives were also made with a digested soyprotein that was obtained as an experimental sample (lot 5-81) fromProf. S. Braun, the Laboratory of Applied Biology at the HebrewUniversity of Jerusalem, Israel. The digested soy protein was preparedas follows. Soy protein isolate (Soy protein isolate SOLPRO 958® SolbarIndustries Ltd, POB 2230, Ashdod 77121, Israel) was suspended in waterat a ratio of 1:10 (w/w). The pH of the suspension was adjusted to pH 7with 10N NaOH, and was then heated to 55° C. while stirring. Neutrase0.8 L® (NOVOZYMES') then was added at a ratio of 20 g per kg of soyprotein, and the mixture was stirred at the same temperature for 4hours. The resulting mixture (pH 6.5) was spray-dried to yield a lighttan powder.

The synthetic method as described in Example 1 (a 1-step method) wasused to make the prepolymers for this example. Each of the prepolymerscontained 15 parts by weight of a protein derivative chosen either fromcastor, whey, or soy (the complete prepolymer compositions are providedin Table 5). The protein derivatives were reacted with one of threecombinations of additional ingredients: (1) 76.5 parts by weight ofRubinate-M PMDI with 8.5 parts by weight of PPG 2000 polyol; (2) 85parts by weight Rubinate-M PMDI alone; or (3) 76.5 parts by weight ofRubinate-M PMDI with 4.25 parts by weight of PPG 2000 polyol and 4.25parts by weight castor oil (Pale Pressed Castor Oil from Alnor OilCompany, Inc.). In each case, the ingredients were simultaneously mixedunder a nitrogen atmosphere at a temperature of 95° C., and were allowedto react for 2 hours. The reaction products then were allowed to cool to25° C. under ambient conditions.

During the prepolymer synthesis, a color change was observed for thesamples containing the castor protein derivatives (JM63-1, JM63-2,JM64-1, JM64-2). This color change occurred at approximately 75° C. Thecolor of the reaction mixture changed from a cloudy tan dispersion to adark brown translucent dispersion. There was a slight color change forthe samples containing the soy protein and the whey protein, but notnearly as significant as that observed for the castor-based prepolymers.In addition, slight foaming was observed for the soy and wheyprepolymers, which was not observed for the castor-containingprepolymers.

TABLE 5 Polyol Type & Dispersion Pre- PMDI Level level Clarity duringstability after polymer (parts by wt.) (parts by wt.) Protein Typesynthesis synthesis JM64-1 76.5 8.5 PPG 2000 Everlase digestedTranslucent Minimal castor (lot 5-83) sedimentation JM63-1 85 NoneEverlase digested Translucent Minimal castor (lot 5-83) sedimentationJM63-2 85 None Digested and Translucent Minimal deaminated castorsedimentation protein (lot 5-82) JM64-2 76.5 4.25 PPG 2000 + Everlasedigested Translucent Minimal 4.25 castor oil castor (lot 5-83)sedimentation JM66-1 76.5 8.5 PPG 2000 Digested soy protein Opaque Largeamount of (lot 5-81) sediment JM66-2 76.5 8.5 PPG 2000 Digested wheyOpaque Large amount of protein (lot 5-80; sediment pH = 3.5)

After each prepolymer reaction was complete (2 hours at 95° C.), theheat of the reactor was turned off, and a catalyst (the same FeAcAc asused in previous Examples) was added to each formulation at aconcentration of 0.1 phr to yield the adhesives shown in Table 6. Thesolutions were stirred for 30 minutes under a nitrogen blanket. Uponcooling, loose sediment was observed to settle to the bottom of theglass containers, and a cloudy supernatant remained on top. The degreeof sedimentation was the greatest for the soy and whey proteins. Thesediments were readily redispersed with stirring (under nitrogen).

The bond strengths of the one-part adhesives to SYP were evaluated via acompressive shear test as described in the previous Examples. 2″×2″×¾″blocks (planed and then surface-sanded) were separated into pairs, andwere pre-conditioned for at least 24 hours at 21° C. and at 65% relativehumidity in an environmental chamber to achieve a bulk-wood moisturecontent of approximately 12%. Each of the adhesives in Table 6 was usedto coat the inner surface of matched wood block pairs (replicates of 6pairs per adhesive). 0.4 to 0.6 g of each adhesive was applied with aplastic pipette, and was then spread with a spatula onto a 2″×1¾″section of a treated-face (only one block per pair was coated withadhesive). The adhesive-coated surface then was sandwiched with thesecond block of the pair, so that the surfaces were in contact with theadhesive over a 2″×1¾″ contact area. This allowed ¼″ of each block tooverhang in “lap-shear” fashion, similar to that described in ASTMD2559. The sandwiched specimens then were cured under pressure (250 psi)for 30 minutes using a Carver press with platen temperatures set at 208°C. During the assembly of the samples (prior to their exposure to thepress cycle), the adhesives remained uncured (no foaming). Afterpressing, all of the adhesives were cured as evidenced by rigidfoam-like characteristics of the excess material that was squeezed outfrom the bondline area. The average compressive shear bond strength and% wood failure for each sample set is given in Table 6.

TABLE 6 Average Bond Strength Average % (peak load at Prepoly- woodfailure failure in pounds) Adhesive mer (+/−S.D.) (+/−S.D.) 64-1 JM64-1 21(+/−20) 870 (+/−450) 64-2 JM63-1 10 (+/−7)  910 (+/−570) 64-3 JM63-284 (+/−15) 4860 (+/−1500) 64-4 JM64-2 9 (+/−7) 630 (+/−470) 64-5 JM66-179 (+/−18) 4280 (+/−1550) 64-6 JM66-2 0 (+/−0) 130 (+/−40) 

These results from Table 6 reveal that the adhesive made with thedigested and deaminated castor protein derivative (64-3) performed muchbetter than the analogous adhesive made with the digested derivativefrom castor (64-2). Thus, when a 1-step synthetic method was employed tomake a 1-part adhesive (i.e., when PMDI was simultaneously mixed andreacted with the protein derivative), the preferred protein derivativewas digested and deaminated protein. An analogous result was observedfor 1-part systems made with whey derivatives (see Example 5). Theseresults collectively demonstrate that the bond-strength performance canbe influenced by the method used to prepare the protein derivatives.Also, based on trends from previous examples, it is worth noting thatfurther performance-enhancements could be possible through theincorporation of an additional catalyst component (i.e., DMDEE), and/orthrough the incorporation of an additional polyol component.

It should be noted that when an adhesive with digested castor was madevia a 1-step process (64-1), the bond strength to SYP was significantlyless than the bond strength that was observed when the same adhesive wasmade via a 2-step process (62-2 from Example 6). This resultdemonstrates that the method of prepolymer synthesis (1-step vs. 2-step)also appears to have a pronounced influence on bond strengthperformance. Thus, when digested castor is used to make a 1-partadhesive, the preferred method of synthesis is a 2-step method (seeExample 6), where the PMDI is first reacted with PPG 2000 to yield anintermediate prepolymer, and where the intermediate prepolymer then issubsequently reacted with the digested castor in a second step to yieldthe final, preferred prepolymer.

Example 8: Epoxy-Based Protein Adhesive

The castor protein derivatives that were used in this example were thesame derivatives that were used in Example 7. A thermally curable epoxyadhesive was prepared by first mixing 1.98 parts of the digested castortogether with 28.57 parts of the digested and deaminated castor proteininto 69.45 parts water (on a weight basis) to yield a 30.55% solidsdispersion (63B1). Next, an epoxy, glycidyl end-capped poly(bisphenolA-co-epichlorohydrin) (CAS Number 25036-25-3, from Sigma-AldrichChemical, Inc.) was mixed with 63B1 at a ratio of 63B1 to epoxy of4.22/1 (w/w) (1.29/1 w/w on a solids basis). The resulting dispersionwas a stable paste that was easily spread with a spatula.

Six pairs of conditioned SYP block shear specimens were prepared andpressed at a pressure of 250 psi, and at a temperature of 208° C. for a30 minute dwell time using procedures as described in Example 7. Uponremoval from the press, the adhesive was noted to have cured asevidenced by the rigidity of a small amount of excess material that hadsqueezed out from the bondline.

The average block shear strength of the specimens was evaluated usingthe procedures reported in Example 7. The average bond strength wasdetermined to be 620 pounds. Inspection of the failed samples revealedthat the failure mechanism was predominantly cohesive failure of thebulk adhesive within the bondline. Further inspection revealed that thebondline adhesive itself was on the order of 0.010″ to 0.015″ inthickness. This result indicates that the adhesive did not flowextensively during the pressing operation, either because of a fast curereaction, or due to a high melt viscosity prior to cure. Either way,because of the thickness of the adhesive in the bondline, and because itfailed cohesively at a high force value, it is apparent that thematerial itself adhered well to wood, and that it was inherently strong.These attributes would render the adhesive as useful in applicationswhere gap-filling characteristics are required. Note that this adhesivecan optionally be mixed in 2-part fashion with isocyanate-basedprepolymers and optionally with primary or secondary amines to achieveenhanced strength (via known epoxy-amine curing mechanisms).

Example 9: Ambient Cure Conditions

The JM64-1 prepolymer that was synthesized for Example 7 was mixed with0.5% by weight DMDEE catalyst. Six pairs of conditioned SYP block shearspecimens were prepared as outlined in Example 7, and were pressed at250 psi for a dwell time of 90 minutes at a platen temperature of 28° C.The samples then were tested for block-shear strength as outlined inExample 7. The average strength was determined to be 2,040 pounds. Thisresult shows that the protein-based adhesives can be selectivelyformulated for use in applications that require ambient cure.

Example 10: Two-Part Adhesive Based on Protein Derivatives from Whey

A two-part curable adhesive according to the invention was formulated byseparately preparing and then mixing two components, a “Part-A”component, and a “Part-B” component.

The Part-A component in this example was the JM30-1 prepolymer describedin Example 1, formulated with 0.1 phr FeAcAc. The composition of thePart-B component is shown in Table 7.

TABLE 7 Level Part-B Composition (weight %) Water 61.8 1,2 Propane diol(PPD) 3.2 Digested whey protein (pH = 6.5) (lot 5-72) 1.8 Digested anddeaminated whey protein (lot 5-41) 33.2

The Part-B mixture formed a stable, creamy dispersion (stable for weeksat 23° C.). In separate experiments, it was determined that theviscosity of the cream was largely dictated by the level of non-solubledigested and deaminated whey protein (PPD and the digested protein weresoluble in water at the levels that were employed). Although a range ofcompositions for Part-B could potentially have been employed, thisparticular composition with approximately 35% protein facilitated theformulation of a 2-part system that not only had a high protein content(this is cost-advantageous), it had the potential of allowing theadhesive to become gap filling (as was observed for the epoxy-proteinsystem in Example 8). Of course, higher solids levels are possible, butthis can come at the expense of increasing the viscosity (which stillcould be desirable in some applications). Lower solids levels could alsobe employed, but this could come at the expense of diminishing theadhesive's gap filling capability (which could also be desirable in someapplications).

In order to prepare the two part adhesive, 1.455 g of Part-A wasvigorously mixed with 15.23 g Part-B under ambient conditions (about 23°C.), which equates to a w/w ratio of B/A of approximately 4/1 (excludingthe volatile water component). The resulting dispersion was used within6 minutes of mixing to prepare six block shear specimens with LodgepolePine using procedures employed in Example 1. The sandwiched specimenswere cured under pressure (214 psi) for 25 minutes using a Carver presswith platen temperatures set at 200° C.

Shortly after mixing, the viscosity was qualitatively observed toincrease with time. In order to test the pot-life of the mixture, twosubsequent sets of samples were prepared at approximately 36 minuteintervals (note that sample preparation time was approximately 6minutes). By the time the third set of specimens was prepared atapproximately 78 minutes after mixing, the mixture had become a thickpaste. Within approximately 3 hours, the mixture had formed a solid massunder ambient conditions. The resulting average block-shear strengthvalues versus time after mixing are given in Table 8.

TABLE 8 Approximate time Average Bond Strength lapse between mixing(peak load at and sample preparation failure in pounds) Sample (minutes)(+/−S.D.) 47-1 6 3490 (+/−350) 47-2 42  290 (+/−200) 47-3 78 189 (+/−40)

The results in Table 8 demonstrate that the resulting two-part reactivemixture (prepared with whey proteins) has a limited pot-life. However,the initial bond strength of the mixture was as good as the comparableone-part adhesive 1-17E (see Example 1) in spite of its overall higherprotein content (approximately 75% protein by weight vs. 10% by weightprotein in 1-17E). Thus, in addition to being water-based (low VOC),gap-filling, and tough when cured, this type of two-part adhesivefacilitates the use of a significantly higher level of protein thanwould otherwise be possible with a one-part system (based on limitationsdiscussed in the previous examples).

Example 11: Two-Part Adhesive Based on Protein Derivatives from Whey

All procedures in this Example, according to the invention, wereidentical to those employed in Example 10. The composition of the Part-Bcomponent is shown in Table 9.

TABLE 9 Level Part-B Composition (weight %) Water 63.2 1,2 Propane diol(PPD) 8.0 Digested whey protein (pH = 6.5) 1.5 Digested and deaminatedwhey protein (lot 5-75) 27.3

36.90 g of Part-B was mixed with 5.03 g the JM30-1 prepolymer as thePart-A (formulated with 0.1 phr FeAcAc) under ambient conditions (about23° C.), which equates to a w/w ratio of B/A of approximately 2.7/1(excluding the volatile water component). The resulting dispersion wasused within 6 minutes of mixing to prepare six block shear specimenswith Lodgepole Pine using procedures identical to those employed inExample 10.

Shortly after mixing, the viscosity was qualitatively observed toincrease with time. In order to test the pot-life of the mixture, twosubsequent sets of samples were prepared at approximately 36 minuteintervals (note that sample preparation time was approximately 6minutes). By the time the third set of specimens was prepared atapproximately 78 minutes after mixing, the mixture had become a thickpaste. Within approximately 3 hours, the mixture had formed a solid massunder ambient conditions. The resulting average block-shear strengthvalues as a function of time after mixing are given in Table 10.

TABLE 10 Approximate time Average Bond Strength lapse between mixing(peak load at and sample preparation failure in pounds) Sample (minutes)(+/−S.D.) 48-1 6 3500 (+/−390)  48-2 42 2220 (+/−1370) 48-3 78  800(+/−1000)

The results in Table 10 show that the resulting two-part reactivemixture has a longer pot-life than the formula used in Example 10;however, the pot-life was still limited. Nevertheless, the initial bondstrength of the mixture was as good as the comparable one-part adhesive1-17E (see Example 1) in spite of its overall higher protein content(approximately 60% protein by weight vs. 10% by weight protein in1-17E). Thus, in addition to being water-based, low VOC, gap-filling,and tough when cured, this type of two-part adhesive facilitates the useof a significantly higher level of protein than would otherwise bepossible with a one part system (based on limitations discussed in theprevious Examples).

Example 12: Two-Part Adhesive Based on Protein Derivatives from Whey

All procedures in this Example, according to the invention, were thesame as those employed in Example 10. The composition of the Part-Bcomponent is shown in Table 11.

TABLE 11 Level Part-B Composition (weight %) Water 64.2 1,2 Propane diol(PPD) 7.8 Digested whey protein (pH 6.5) 1.4 Digested and deaminatedwhey protein (lot 5-75) 26.6

37.90 g of Part-B was mixed with 9.69 g of the JM30-1 prepolymer asPart-A (formulated with 0.1 phr FeAcAc) under ambient conditions (about23° C.), which equates to a w/w ratio of B/A of approximately 1.4/1(excluding the volatile water component). The resulting dispersion wasused within 6 minutes of mixing to prepare six block shear specimenswith Lodgepole Pine using procedures identical to those employed inExample 10.

Shortly after mixing, the viscosity was qualitatively observed toincrease with time. The viscosity of the mixture was observed toincrease more quickly than the mixtures used in Examples 10 and 11. Forthis reason, only two sets of samples were prepared, the second set wasprepared approximately 36 minutes after the first set. By the end of thesecond set's press cycle (t=78 minutes after mixing), the mixture hadsolidified, and could no longer be used. The resulting averageblock-shear strength values as a function of time after mixing are givenin Table 12.

TABLE 12 Approximate time Average Bond Strength lapse between mixing(peak load at and sample preparation failure in pounds) Sample (minutes)(+/−S.D.) 49-1 6 4900 (+/−680) 49-2 42 2710 (+/−900)

In spite of the short pot-life, the initial bond strength of the mixturewas better than the comparable one-part adhesive 1-17E (see Example 1).This was surprising when one considers that the 2-part system in itscured state has a projected protein content of approximately 50% vs. 10%by weight protein in 1-17E. Thus, in addition to being water-based, lowVOC, gap-filling, and tough when cured, this type of two-part adhesivefacilitates the use of a significantly higher level of protein thanwould otherwise be possible with a one part system (based on limitationsdiscussed in the previous Examples).

Example 13: Two-Part Adhesive Based on Protein Derivatives from Whey andEVA (Thermoset and Thermoplastic Types)

All sample preparation procedures in this Example were the same as thoseemployed in Example 10 with one exception: the block shear specimenswere pressed at a pressure of 250 psi for 30 minutes using a Carverpress with platen temperatures set at 200° C. (6 pairs per cycle).

The “Part-A” component in this example was the JM30-1 prepolymerformulated with 0.1 phr FeAcAc from Example 1 (comprised of 73.81 partsPMDI, 16.19 parts PPG 2000, 10 parts of Flavourzyme digested wheyprotein (weight basis), and formulated with 0.1 phr FeAcAc).

The Part-B component in this Example was also formulated with anadditional ingredient: poly(ethylene-co-vinyl acetate-co-methacrylicacid), commercially known as Airflex 426 (obtained from Air Products)and herein referred to as “EVA.” The latex was gravimetricallydetermined to be 63% solids by weight. The percentage of water in thelatex was taken into account when determining the total level of waterin the formula. The composition of the Part-B component is shown inTable 13.

TABLE 13 Level Part-B Compositions (weight %) Water 50.3 EVA (on asolids basis) 27.6 Digested whey protein (pH = 6.5) 4.3 Digested anddeaminated whey protein (lot 5-75) 17.8

7.45 g of Part-A was mixed with 15 g of Part-B under ambient conditions(about 23° C.), which equates to a w/w ratio of B/A of approximately 1/1(excluding the volatile water component). The viscosity of the resultingdispersion was observed to noticeably increase within the first 5minutes after mixing. This rate of viscosity rise was faster than hadbeen observed for the analogous 2-part systems made in Examples 10-12.In fact, after approximately 1 hour, the mixture had turned into a rigidsolid in its container. It was only possible to prepare 1 group of blockshear specimens (the wood used in this example was Lodgepole Pine). Inaddition, samples were also made by using the Part-B component alone asan adhesive—in the absence of the Part-A curative. The resulting averageblock-shear strength values are given in Table 14.

TABLE 14 Average Bond Strength (peak load at Sample failure in pounds)(+/−S.D.) 50-1 (Part-B alone) 520 (+/−250) 50-2 (2-part mixture) 3700(+/−1700)

In spite of the short pot-life, the initial bond strength of thetwo-part mixture was similar to the comparable one-part adhesive 1-17E(see Example 1). This is particularly surprising when one considers thatthe two-part system in its cured state had a sum total protein contentof approximately 27% vs. 10% by weight protein in 1-17E.

The bond strength of Part-B alone was inferior to that of the two-partsystem. In a separate experiment, additional samples were pressed forthe purpose of determining whether or not they could be pulled apart byhand immediately upon removal from the press (while hot). The samplesmade with the two-part system could not be pulled apart, and the excessmaterial that squeezed out from the bondline was rigid. Conversely,while they were still hot, the samples made with Part-B alone wereeasily pulled apart. However, when they were pressed back together byhand (i.e., before they were allowed to cool), the Part-B specimensformed a stable bond, and the samples could not be pulled apart by handunder ambient conditions at 25° C. These results indicate that Part-Balone behaves like a reversible thermoplastic adhesive, whereas thetwo-part system behaves like a thermoset.

Thus, in addition to being water-based, low VOC, gap-filling, and toughwhen cured, this type of adhesive can optionally be used to yield areversible thermoplastic adhesive (by omitting the Part-A curative).This could be beneficial in adhesive applications that either tolerateor mandate thermoplastic behavior.

Example 14: Two-Part Adhesive Based on Protein Derivatives from Whey andEVA

All sample preparation procedures in this Example were the same as thoseemployed in Example 13. The Part-B component in the Example was also thesame as that used in Example 13.

15 g of Part-B was mixed with 7.45 g the JM26-3 prepolymer (as Part-A),described in Example 2 (formulated with 0.1 phr FeAcAc) under ambientconditions (about 23° C.), which equates to a w/w ratio of B/A ofapproximately 1/1 (excluding the volatile water component). Theviscosity of the resulting dispersion was observed to noticeablyincrease within the first 5 minutes after mixing. This rate of viscosityrise was faster than had been observed for the analogous two-partsystems made in Examples 10-12. After approximately 1 hour, the mixturehad turned into a rigid solid in its container. It was only possible toprepare 1 group of block shear specimens (the wood used in this examplewas Lodgepole Pine). The resulting average block-shear strength value(averaged from 6 specimens) was determined to be 3,400 (+/− 1600)pounds. In spite of the short pot-life and higher protein content, theinitial bond strength of the two-part mixture was nearly double that ofthe comparable one-part adhesive 52-1 (52-1 had a bond strength ofapproximately 1,300 pounds—see Example 2). This is surprising when oneconsiders that the two-part system in its cured state had a sum totalprotein content of approximately 29% vs. 13% by weight protein in 52-1.

Example 15: Two-Part Adhesive Based on Protein Derivatives from Whey andEVA

All sample preparation procedures in this Example were the same as thoseemployed in Example 13. The composition of the Part-B component is shownin Table 15.

TABLE 15 Level Part-B Composition (weight %) Water 54.6 EVA (on a solidsbasis) 25.2 Digested and deaminated whey protein (lot 5-75) 20.2

In one case (sample 53-1), 15 g of Part-B was mixed with 7.45 g of theJM26-3 prepolymer (as Part-A) from Example 2 (formulated with 0.1 phrFeAcAc) under ambient conditions (about 23° C.), which equates to a w/wratio of B/A of approximately 1.4/1 (excluding the volatile watercomponent). In a second case, the same mixture was created, but theFeAcAc was omitted from the formulation (sample 53-2).

The viscosities of the resulting dispersions were observed to increasenoticeably within the first 5 minutes after mixing. This rate ofviscosity rise was faster than had been observed for the analogous2-part systems made in Examples 10 through 12. In fact, afterapproximately 1 hour, the mixtures had turned into rigid solids in theirrespective containers. For this reason, it was only possible to prepare1 group of block shear specimens for each (the wood used in this examplewas Lodgepole Pine). The resulting average block-shear strength valuesare given in Table 16.

TABLE 16 Average Bond Strength (peak load at Sample failure in pounds)(+/−S.D.) 53-1 4550 (+/−1280) 53-2 3030 (+/−1360)

In spite of the short pot-life, the initial bond strengths of thetwo-part mixtures were surprisingly higher than the comparable one-partadhesive 52-1 (see Example 2). This is surprising when one considersthat the two-part system in its cured state had a sum total proteincontent of approximately 31% vs. 13% by weight protein in 52-1. Alsosurprising is the fact that even the sample without the FeAcAc catalystcured sufficiently enough to achieve considerably higher bond strengththan its 52-1 counterpart.

Example 16: Two-Part Adhesive Based on Protein Derivatives from Castor

The sample preparation procedures in this Example were identical tothose employed in Example 13. The Part-A reactive component of thisexample was composed of the same adhesive used to prepare sample 61-2 inExample 6 (85/15 w/w Rubinate-M PMDI/digested castor protein with 0.1phr FeAcAc). The composition of the Part-B component is shown in Table17.

TABLE 17 Level Part-B Composition (weight %) Water 69.45 Digestedprotein from castor (lot 5-83) 1.98 Digested and deaminated castor 28.57protein (lot 5-82)

35.28 g of Part-B was mixed with 8.35 g Part-A under ambient conditions(about 23° C.), which equates to a w/w ratio of B/A of approximately1.29/1 (excluding the volatile water component). The resultingdispersion had a considerably longer pot-life than the two-part systemsfrom previous Examples (the viscosity did not noticeably change during a1.5 hour period of observation). A single set of six SYP block shearspecimens were prepared within 6 minutes after mixing the sample. Thesamples were pressed at a pressure of 250 psi in a Carver press for adwell time of 30 minutes with platen temperatures set at 205° C. Theresulting average block-shear strength of this set (60-1) was determinedto be 4,060 (+/− 600) pounds with 73% average wood failure.

The bond strength of this two-part mixture was significantly higher thanthe comparable one-part adhesive 61-2 (200 pounds; see Example 6). Thisis surprising when one considers that the 2-part system in its curedstate had a sum total protein content of approximately 63% vs. 15% byweight protein in 61-2. Thus, in addition to being water-based (lowVOC), gap-filling, and tough when cured, this type of two-part adhesivefacilitates the use of a significantly higher level of protein thanwould otherwise be possible with a one-part system (based on limitationsdiscussed in the previous Examples), while simultaneously providingenhanced bond strength to SYP.

Example 17: Two-Part Adhesive Based on Protein Derivatives from CastorWith and without EVA

The sample preparation procedures in this Example were the same as thoseemployed in Example 13 with two exceptions: the block shear specimenswere made with SYP, and they were pressed at a pressure of 250 psi for30 minutes using a Carver press with platen temperatures set at 208° C.(6 pairs per cycle). The “Part-A” curative components for this Examplewere chosen from the adhesives that were used as one-part adhesives inExamples 6 and 7 (the compositions are given in Tables 4, 5, and 6). ThePart-A components were all formulated with 0.1 phr FeAcAc.

The Part-B component compositions for this Example are given in Table18. Note that Part-B1 is the same as that used in Example 16, whilePart-B2 contains an additional EVA ingredient. Both Part-B mixtures wereformulated to have similar viscosities. The compositions of theresulting 2-part adhesives for this example (Part-A+Part-B) are providedin Table 19 together with average block shear strengths and wood-failurepercentages for SYP block-shear specimens.

TABLE 18 “Part-B1” “Part-B2” Part-B Composition (weight %) (weight %)Water 69.45 62.13 Digested protein from castor (lot5-83) 1.98 2.41Digested and deaminated castor protein 28.57 25.03 (lot 5-82) Airflex426 EVA (solids basis) 0 10.43

TABLE 19 Average Bond Strength B/A ratio to SYP Part Part (solids basis% protein (peak load B1 B2 excluding by wt. in % wood at failure, Samplelevel level Part A Component and volatile cured failure lbs.) ID (g) (g)Level (g) water) adhesive (+/−S.D.) (+/−S.D.) 63-1 8.44 0 62-4 (90/10(w/w) 1.29/1 56.3 29 (+/−27) 2400 (+/−2000) PMDI/PPG 2000), 2.0 g 63-2 08.44 62-4 (90/10 (w/w)  1.6/1 44.6 70 (+/−26) 4690 (+/−2000) PMDI/PPG2000), 2.0 g 63-4 8.44 0 62-2 (2-step synthesis; 1.29/1 62.9 5 (+/−5)900 (+/−900) 76.5/8.5/15 w/w/w PMDI/PPG2000/digested castor), 2.0 g 63-50 8.44 62-2 (2-step synthesis;  1.6/1 50.35 38 (+/−24) 570 (+/−280)76.5/8.5/15 w/w/w PMDI/PPG2000/digested castor), 2.0 g 65-1 6.55 0 64-1(1-step synthesis;   1/1 57.5 60 (+/−30) 2350 (+/−1260) 76.5/8.5/15w/w/w PMDI/PPG2000/digested castor), 2.0 g 65-2 0 6.55 64-1 (1-stepsynthesis; 1.24/1 46.8 84 (+/−14) 4330 (+/−460)  76.5/8.5/15 w/w/wPMDI/PPG2000/digested castor), 2.0 g 65-3 6.55 0 64-2, (1-stepsynthesis;   1/1 57.5 44 (+/−36) 2640 (+/−1340) 85/15 w/w PMDI/ digestedcastor), 2.0 g 65-4 0 6.55 64-2, (1-step synthesis; 1.24/1 46.8 99(+/−1)  4300 (+/−520)  85/15 w/w PMDI/ digested castor), 2.0 g 65-5 6.550 64-3, (1-step synthesis;   1/1 57.5 52 (+/−18) 2630 (+/−1240) 85/15w/w PMDI/ Digested and deaminated castor protein), 2.0 g 65-6 0 6.5564-3, (1-step synthesis; 1.24/1 46.8 73 (+/−20) 3120 (+/−3000) 85/15 w/wPMDI/ Digested and deaminated castor protein), 2.0 g 65-7 6.55 0 64-4,(1-step synthesis;   1/1 57.5 17 (+/−5)  740 (+/−17)  76.5/4.25/4.25/15w/w/w/w PMDI/PPG2000/castor oil/digested castor), 2.0 g 65-8 0 6.5564-4, (1-step synthesis; 1.24/1 46.8 79 (+/−13) 3880 (+/−890) 76.5/4.25/4.25/15 w/w/w/w PMDI/PPG2000/castor oil/digested castor), 2.0g

Analysis of these results leads to several observations. Viscosity andpot-life observations—like the castor-based two-part adhesive of Example16, all of the two-part adhesives in this example had a considerablylonger pot-life than those that were made with analogous whey proteins.Specifically, the viscosity did not qualitatively change during a 1.5hour period of observation. Thus, unlike comparable adhesives that wereprepared with the whey protein derivatives (e.g., see Examples 13, 14,and 15), the adhesives prepared with castor-based proteins weresurprisingly stable. This enhanced stability would be beneficial duringassembly operations that require longer “work times.” Thus, when longwork-times are desired, castor-based protein derivatives are thepreferred protein components in two-part adhesive systems.

The performance of two-part system was compared against the one-partsystem when using identical reactive components. The performance of theanalogous one-part and two-part systems containing castor proteins arecompared in Table 20. As noted previously, one-part systems (containingcastor protein derivatives) were observed to yield the best performancewhen they were made with either a digested castor-based prepolymer thatwas synthesized in a 2-step process, or when they were made with andigested and deaminated protein-containing prepolymer (from castor) thatwas synthesized in a 1-step process.

It was observed that, for the two-part systems, the worst performancewas achieved when the digested castor-based prepolymer was synthesizedin a 2-step process. In addition, the 2-part system that was made with aprepolymer containing digested and deaminated castor protein wasobserved to perform worse than its 1-part analog. Conversely, the bestperformance for two-part systems was achieved when the Part-A componentwas composed of a prepolymer that was synthesized with digested castorin a 1-step process (e.g. 65-2, 65-4, 65-8). In fact, all such two-partsystems performed significantly better than their 1-part analogs—inspite of their higher protein contents (nearly 50% in the 2-part systemsvs. 15% in the 1-part systems).

TABLE 20 % wood failure & av. % wood 1-Part block shear % 2-Part failure& Adhesive & strength protein Adhesive as Use of av. block % referenced(lbs.) for by wt. made in the EVA shear protein example Part A Proteinin present in strength by wt. (i.e., Part-A Part A alone (fromderivative example example 2-part from 2-part in in present Synthesisprevious contained Part-A (i.e., Part-A + system adhesive 2-partexample) Method examples) in Part-A alone Part-B) (Y/N) (lbs) adhesive62-2 (ex. 6) 2-step 79/4710 Digested 15 63-4 (ex. 17) N 5/900 62.9castor 62-2 (ex. 6) 2-step 79/4710 Digested 15 63-5 (ex. 17) Y 38/57050.35 castor 64-1 (ex. 7) 1-step 21/870 Digested 15 65-1 (ex. 17) N60/2350 57.5 castor 64-1 (ex. 7) 1-step 21/865 Digested 15 65-2 (ex. 17)Y 84/4330 46.8 castor 64-2 (ex. 7) 1-step 10/911 Digested 15 65-3 (ex.17) N 44/2640 57.5 castor 64-2 (ex. 7) 1-step 10/911 Digested 15 65-4(ex. 17) Y 99/4300 46.8 castor 64-3 (ex. 7) 1-step 84/4860 Digested, 1565-5 (ex. 17) N 52/2630 57.5 deaminated protein 64-3 (ex. 7) 1-step84/4860 Digested, 15 65-6 (ex. 17) Y 73/3120 46.8 deaminated protein64-4 (ex. 7) 1-step  9/630 Digested 15 65-7 (ex. 17) N 17/740 57.5castor 64-4 (ex. 7) 1-step  9/630 Digested 15 65-8 (ex. 17) Y 79/388046.8 castor

With regard to the EVA components, with the exception of sample 63-5,which employed a prepolymer that was synthesized in 2 steps, the use ofEVA as an ingredient in the Part-B component led to an improvement inbond strength for all samples. In fact, the best performing sample (65-4with 99% wood failure) contained approximately 46.8% protein, 37.9%PMDI, and 15.3% EVA. One of the most extreme improvements occurred whenEVA was added to the two-part system containing a Part-A made with bothcastor oil and digested castor protein (compare 65-8 to 65-7). Thistwo-part system was not only better than its 1-part analog, thepercentage of wood failure increased from 17% to 79% when EVA was added.Thus, as demonstrated in this Example, it is possible to makepredominantly protein-based adhesives with strengths that aresurprisingly high enough to exceed the strength of the SYP wood itself.

Example 18: Effect of Enzyme Concentration on One-Part AdhesivesPrepared with Digested Castor and with a Derivative Made Therefrom

Adhesives in this Example included either an Everlase digested proteinfrom castor (experimental sample lot 5-90), or a digested and deaminatedcastor protein derivative (experimental sample lot 5-92). Both materialswere obtained from Prof. S. Braun, the Laboratory of the Department ofApplied Biology at the Hebrew University of Jerusalem, Israel. Thedigested castor in this example was prepared and dried according to theprocedures described in Example 6 with one exception: the Everlase 16LType EX® (NOVOZYMES') was added at a ratio of 20 g per kg of castor mealprotein (double the level used in Example 6). Similarly, the digestedand deaminated protein derivative was prepared according to theprocedures outlined in Example 7, but the enzyme concentration wasdoubled (lot 5-83). The doubling of the enzyme concentration was done inorder to lower the relative molecular weights of the digested fractionsso as to determine whether adhesives could be prepared with highereffective protein concentrations than those prepared in Examples 6 and7, while simultaneously maintaining equivalent or lower relativeviscosities. The relative viscosities of adhesives as reported in thisexample were qualitatively evaluated by means of visual observation(i.e., by judging the relative pourability from either an open containeror from a closed container upon tilting), and by means of hand-stirringthe adhesives with a spatula.

The adhesives in this example were prepared using the same procedures asreported in Examples 6 and 7. The adhesives were also used to prepareSYP block shear specimens in accord with the procedures outlined inExample 4. Comparative adhesives were also made with digested soyprotein (lot 5-81 made via procedures outlined in Example 7). Thecompositions of the adhesives and resulting average block shearstrengths are given in Table 21, together with % wood failure in accordwith the D905 and D2559 ASTM standards.

Data from Examples 6 and 7 are also reproduced in Table 21 forcomparative purposes. Qualitative viscosity comparisons are provided inTable 22.

TABLE 21 Average Bond Strength Average (peak load PMDI-based Additional% wood at failure in Synth. Protein Type and component Catalyst failurepounds) Sample Method % by weight (% by weight) (phr) (+/− S.D.) (+/−S.D.) 62-1-81-1 2-step 15% digested 85% 90/10 (w/w) 0.13  75 (30) 3800(1600) castor (lot 5-90) PMDI/PPG 2000 DMDEE 62-1 (ex. 6) 2-step 15%digested 85% 90/10 (w/w) 0.13  97 (3) 6070 (380) castor (lot 5-83)PMDI/PPG 2000 DMDEE 62-3-81-1 2-step 15% digested 85% JM62-2 0.13  30(20) 2540 (1080) castor (lot 5-90) 90/10 (w/w) DMDEE PMDI/PPG 2000 +0.1% FeAcAc 62-3 (ex. 6) 2-step 15% digested 85% JM62-2 0.13 100 (0)6000 (1050) castor (lot 5-83) 90/10 (w/w) DMDEE PMDI/PPG 2000 + 0.1%FeAcAc 64-4 (ex. 7) 1-step 15% digested 85% 90/10   0  9 (7)  630 (470)castor (lot 5-83) (w/w) PMDI/PPG 2000 + 0.1% FeAcAc 83-3-83-1 1-step 25%digested 75% 90/10 0.13  30 (30) 3270 (1570) castor (lot 5-83) (w/w)DMDEE PMDI/PPG 2000 + 0.1% FeAcAc 83-2-83-1 1-step 25% digested 75%90/10 (w/w) 0.13  9 (6) 1630 (1400) castor (lot 5-90) PMDI/PPG 2000 +DMDEE 0.1% FeAcAc 83-8-84-1 1-step 25% digested 75% 90/10 (w/w)   0  0 200 (80) castor (lot 5-90) PMDI/PPG 2000 + 0.1% FeAcAc 83-4-83-1 1-step30% digested 70% PMDI + 0.13  6 (5)  300 (270) castor (lot 5-90) 0.1%FeAcAc DMDEE 64-3-81-1 1-step 15% digested & 85% PMDI +   0  80 (15)5130 (1030) deaminated castor 0.1% FeAcAc protein (lot 5-92) 64-3 (ex.6) 1-step 15% digested & 85% PMDI +   0  84 (15) 4860 (1500) deaminatedcastor 0.1% FeAcAc protein (lot 5-82) 71-1-82-1 1-step 15% digested &85% PMDI + 0.13 Not Not deaminated castor 0.1% FeAcAc DMDEE testedtested 71-3-82-1 1-step 15% digested & 85% JM62-2   0  97 (3) 5080 (650)deaminated castor 90/10 (w/w) protein (lot 5-92) PMDI/PPG 2000 + 0.1%FeAcAc 71-4-82-1 1-step 15% digested & 85% JM62-2 0.13  90 (7) 6190(1100) deaminated castor 90/10 (w/w) DMDEE protein (lot 5-92) PMDI/PPG2000 + 0.1% FeAcAc 83-5-84-1 1-step 30% digested & 70% PMDI + 0.13  84(13) 5700 (1200) deaminated castor 0.1% FeAcAc DMDEE protein (lot 5-92)64-5 (ex. 7) 1-step 15% digested soy 85% 90/10 (w/w)   0  79 (18) 4280(1550) protein (lot 5-81) PMDI/PPG 2000 + 0.1% FeAcAc 64-5-82-1 1-step15% digested soy 85% 90/10 (w/w)   0  90 (8) 4480 (690) (repeat ofprotein (lot 5-81) PMDI/PPG 2000 + ex. 7 64-5) 0.1% FeAcAc 71-2-82-11-step 15% digested soy 85% 90/10 (w/w) 0.13  90 (20) 5400 (1400)protein (lot 5-81) PMDI/PPG 2000 + DMDEE 0.1% FeAcAc 64-2 (ex .7) 1-step15% digested 85% PMDI +   0  10 (7)  910 (570) castor (lot 5-83) 0.1%FeAcAc 65-4A-83-1 1-step 15% digested 85% PMDI +   0  7 (7) 1190 (1270)castor (lot 5-90) 0.1% FeAcAc JM362-2 1-step 25% digested 75% PMDI   0Not Not castor (lot 5-90) 0.1% FeAcAc tested tested 83-6-84-2 N/A none100% PMDI + 0.13  97 (3) 5400 (980) 0.1% FeAcAc DMDEE 83-7-84-1 N/A none100 % PMDI +   0  98 (2) 5060 (1040) 0.1% FeAcAc

The data in Table 21 reveal several trends. Consistent with priorExamples, results of one-part adhesives prepared with the castor proteinderivative were found to perform better than the analogous adhesivesprepared with otherwise equivalent weight percents of digested castor(via the 1-step synthetic method). This trend was independent of theenzyme concentration during the digestion process, and was alsoindependent of the weight percent of the protein in the adhesive (overthe range that was evaluated).

Adhesives that were prepared with a polyol and digested castor protein(synthesized via a 2-step synthetic process) were observed to performthe best when the digested castor was prepared with a lower enzymeconcentration.

Unlike the adhesives prepared with digested castor, the bond-strengthcharacteristics of analogous adhesives prepared with the castorderivative were found to be essentially unaffected by the use of ahigher enzyme concentration during the digestion process.

Among the adhesives prepared with the castor derivative, bond strengthperformance was observed to be minimally affected by the concentrationof the protein in the adhesive—at least over the range that wasevaluated in this example (83-5-84-1 vs. 64-3-81-1 & 64-3).

Adhesives prepared with the castor derivative were observed to performcomparably to adhesives containing no protein at all, the bond strengthsgenerally exceeded the strength of the wood itself (71-3-82-1,71-4-82-1, 64-3-81-1, 64-3, and 83-5-84-1 versus 83-6-84-2 and83-7-84-1).

Adhesives prepared with digested soy protein (synthesized via a 1-stepsynthetic process) were observed to perform better than analogousadhesives prepared with digested castor (also synthesized in a 1-stepprocess), and on par with adhesives prepared with digested anddeaminated castor protein.

Like the derivatized castor, digested soy that was used in this examplealso contains fewer free carboxylic acids, acid salts, and amine saltsthan the digested castor. When coupled with viscosity observations (tobe discussed below), these results suggest that in preparing a one-partadhesive, it is desirable that the levels of free carboxylic acids, acidsalts, and amine salts be controlled and/or minimized, particularly ifit is desirable for the adhesive to contain higher levels of protein.

The relative viscosity trends as shown in Table 22, indicate that theuse of a higher enzyme level during the digestion of castor facilitatethe incorporation of higher levels of protein into the adhesive withoutadversely affecting viscosity. However, as mentioned previously, higherlevels of digested castor were observed to have a negative impact onbond-strength performance. This problem was overcome with the use ofderivatized castor (prepared from castor that was digested at a higherenzyme level), which not only facilitated the use of higher proteinlevels, but did so without adversely affecting bond-strengthperformance.

Qualitative viscosity comparisons of adhesives prepared in this Examplewith those reported in Examples 6 and 7 are set forth in Table 22.

TABLE 22 Qualitative Viscosity Trend Formulation Factor 62-1-81-1 (notpourable, paste-like) < 62-1 (not Higher enzyme level pourable,paste-like); during castor di- 62-3-81-1 (not pourable, paste-like) <62-3 (not gestion led to a pourable, paste-like); lower viscosity ad-64-3-81-1 (pourable) < 64-3(pourable); hesive 83-3-83-1 (not pourable,paste-like) > 83-2-83-1 (not pourable, paste-like) 65-4A-83-1 (pourable)< 64-2 (pourable) 64-5-82-1, 64-5, and 71-2-82-1 (all not Digested soyproduced pourable, paste-like) > 64-4, 71-3-82-1, and higher viscosityad- 71-4-82-1 (all pourable) hesives than digested castor andderivatized castor 83-4-83-1 (not pourable, paste-like) > Higher levelsof di- 65-4A-83-1 (pourable) gested castor led to higher viscosity ad-hesives 83-5-84-1 (thick but pourable) > 71-1-82-1 Higher levels of de-(pourable) rivatized castor led to higher viscosity adhesives 83-5-84-1(thick but pourable) << 83-4-83-1 Derivatized castor led (not pourable,paste-like) to lower viscosity ad- hesives than adhesives made withequal levels of digested castor

The following procedure was used for obtaining FTIR spectra on proteinsamples. Spectra were acquired on solid samples (powders) using a BrukerALPHA™ solid state FTIR spectrometer equipped with a diamond ATR cell(24 scans, 4 cm⁻¹ resolution). The spectra were vertically scaled toachieve equivalent absorbance intensities for the common bands centerednear 1625-1640 cm⁻¹. Tentative absorption assignments were made based onliterature assignments for similar compounds as reported inSpectroscopic Identification of Organic Compounds, 4th edition, R. M.Silverstein, G. C. Bassler, and T. C. Morrill, John Wiley & Sons, NewYork, N.Y., 1981; and in Introduction to Infrared & Raman Spectroscopy,3rd Edition, N. B. Colthup, L. H., Daly, and S. E. Wiberley, AcademicPress, Inc., New York, N.Y., 1990. As shown in FIG. 4, the digestedcastor protein exhibits the presence of a well-defined carbonyl stretchcentered near 1715 cm⁻¹, which is consistent with the presence of acarboxylic acid. The ratio of this absorbance to the common amide-I bandcentered near 1640 cm⁻¹ is higher in the digested castor protein than inboth the digested and deaminated castor protein, and in the digested soyprotein. In addition, the digested castor contains absorbance bands thatare consistent with the presence of amine salts. These moieties areassociated with the water-soluble fraction that is present in thedigested castor (at a concentration of about 50% by weight).

Example 19: Effects of Enzyme Concentration and Post-Mix Time on thePerformance of Two-Part Adhesives Prepared with Digested Castor and aCastor Derivative

The sample preparation procedures in this Example were the same as thoseemployed in Examples 13 and 17 with one exception: the block shearspecimens (SYP) were pressed for 35 minutes using a Carver press withplaten temperatures set at 208° C. (6 pairs per cycle).

Several different “Part-A” curative components were used in thisExample, including: sample 65-4A-83-1 (from Example 18), sample 64-2(from Example 7) which contained digested castor that was prepared withhalf the enzyme level of 65-4A-83-1, and sample JM362-2 (from Example18). The Part-A components were all formulated with 0.1 phr FeAcAc. ThePart-B component compositions for this example are given in Table 23.

TABLE 23 84-3B 85-2B Part-B Composition (weight %) (weight %) Water62.13 62.13 Digested protein from castor (lot 5-90) 2.41 24.77 Digestedand deaminated castor protein 25.03 0 (lot 5-92) Airflex 426 EVA (solidsbasis) 10.43 10.43 % total solids 37.87 37.87 % protein (dry basis)72.46 72.46

Note that 84-3B in this Example, like the analogous “Part-B2” of Example17, also employed digested castor and the digested and deaminated castorprotein. However, the protein components in this example were digestedwith double the concentration of enzyme. The Part-B component labeled“85-2B” contained of only digested castor (lot 5-90). The digestedcastor itself was implicitly contained two fractions: a water-solublefraction, and a water-insoluble/water dispersible fraction. This will bediscussed in greater detail in Example 20.

The compositions of the resulting two-part adhesives for this example(Part-A+Part-B) are provided in Table 24 together with average blockshear strengths and wood-failure percentages for SYP block-shearspecimens. Note that in many cases, multiple sample sets weresequentially prepared from the same batch of adhesive as a function oftime so that the pot-life could be evaluated after mixing.

TABLE 24 Time B/A ratio Average between (solids Bond mixing basis %protein Strength to Part B and excluding by wt. in % wood SYP (peak loadlevel (g) & Part A Component and pressing volatile cured failure atfailure, lbs.) Sample ID type Level (g) (min.) water) adhesive (+/−S.D.) (+/− S.D.) 65-4 Part-B2 64-2, (1-step synthesis;  6 1.24/1 46.8 99(1) 4300 (520) (ex. 17) (Ex 17); 85/15 w/w PMDI/digested 6.55 gcastor-lot 5-83), 2.0 g 65-4-85-1 84-3B; 65-4A-83-1, (1-step synthesis; 6 1.24/1 46.8 90 (10) 5530 (680) 6.55 g 85/15 w/w PMDI/digestedcastor-lot 5-90), 2.0 g 65-4-85-2 84-3B; 65-4A-83-1, (1-step synthesis;30 1.24/1 46.8 90 (15) 6120 (1090) 6.55 g 85/15 w/w PMDI/digestedcastor-lot 5-90), 2.0 g 85-1-1 84-3B; JM362-2, (1-step synthesis;  61.24/1 51.3 80 (30) 4840 (980) 6.55 g 75/25 w/w PMDI/digested castor-lot5-90), 2.0 g 85-1-2 84-3B; JM362-2, (1-step synthesis; 40 1.24/1 51.3 80(10) 5500 (1500) 6.55 g 75/25 w/w PMDI/digested castor-lot 5-90), 2.0 g86-2-1 85-2B; 64-2, (1-step synthesis; 85/15  6 1.24/1 46.8 80 (15) 3780(1620) 6.55 g w/w PMDI/digested castor-lot 5-83), 2.0 g 87-1-1 85-2B;65-4A-83-1, (1-step synthesis;  6 1.24/1 46.8 50 (40) 3100 (2600) 6.55 g85/15 w/w PMDI/digested castor-lot 5-90), 2.0 g 87-1-2 85-2B;65-4A-83-1, (1-step synthesis; 35 1.24/1 46.8 70 (25) 4200 (2000) 6.55 g85/15 w/w PMDI/digested castor-lot 5-90), 2.0 g 65-4-85-3 84-3B;65-4A-83-1, (1-step synthesis;  6 1.24/1 46.8 97 (4) 5920 (1450) 6.55 g85/15 w/w PMDI/digested castor-lot 5-90), 2.0 g 65-4-85-4 84-3B;65-4A-83-1, (1-step synthesis; 35 1.24/1 46.8 93 (8) 6080 (1430) 6.55 g85/15 w/w PMDI/digested castor-lot 5-90), 2.0 g

Several observations were made during the mixing of the samples. Inaddition, the data in Table 24 reveal several trends. Upon comparinganalogous formulas, it can be seen that the performance of two-partadhesives was not significantly affected by the use of a higher enzymeconcentration during digestion (65-4 vs. 65-4-85-1, 65-4-85-2,65-4-85-3, and 65-4-85-4). In each of these cases, the strength of theadhesive exceeded the strength of the wood itself

The bond strength performance of two-part adhesives was adverselyaffected by the use of 85-2B as the Part-B component, which contained anexcess of digested castor (86-2-1, 87-1-1, and 87-1-2). Conversely, whenthe level of digested castor was minimized, and when the digested anddeaminated derivative was used in its place, the performance wasdramatically improved (65-4-85-1, 65-4-85-2, 65-4-85-3, and 65-4-85-4).In a separate experiment (see Example 20), the digested castor wasdetermined to contain about 50% by weight of a water-insoluble/waterdispersible fraction, and about 50% by weight of an entirelywater-soluble fraction (comprised of free carboxylic acids, acid salts,and amine salts). As will be discussed in Example 20, when thiswater-soluble fraction was removed, the performance of comparabletwo-part adhesives was dramatically improved. Like thewater-insoluble/water dispersible fraction from digested castor, thedigested and deaminated derivative that was used in the Part-B componentlabeled 84-3B was also determined to be water-insoluble, anddispersible. These results demonstrate that in order to optimize theperformance of two-part adhesives, it is desirable to maximize the useof protein components that are water-dispersible, and to minimize thosecomponents that are water-soluble. As noted in Example 18, thewater-soluble components can be identified by means of solid state FTIRanalysis. Further analysis is provided in Example 20. For the case ofdigested castor, these components were discovered to be typicallycomprised of free carboxylic acids, acid salts, and amine salts.

The presence of a high fraction of digested castor in the Part-Bcomponent (85-2B) was also observed to have an impact on the timerequired to achieve homogeneity during mixing, as well as on theultimate bond strength. In comparing samples made with 85-2B containingdigested castor with EVA (86-2-1, 87-1-1 and 87-1-2) to those made with84-3B containing predominantly digested and deaminated castor protein(65-4-85-1, 65-4-85-2, 65-4-85-3, and 65-4-85-4), the later set wasobserved to be significantly more homogeneous upon mixing. For example,when the A and B parts of sample 86-2-1 were mixed, the part-A componentwas observed to form heterogeneous droplets that were difficult todisperse. When sample 87-1-1 was mixed, it exhibited similar behavior.In contrast, upon mixing the A and B parts of samples 65-4-85-1,65-4-85-2, 65-4-85-3, and 65-4-85-4, homogeneity was immediately andeasily achieved. In addition, these samples produced block shearspecimens with superior bond strengths. These results demonstrate thatbond strength performance can also be impacted by the homogeneity of theadhesive. Thus, in order to achieve optimal bond strength, it isdesirable to achieve optimal homogeneity upon mixing. Given that thePart-A component is water-insoluble, homogeneity becomes increasinglydifficult to achieve when the Part-B component is predominantlywater-soluble. Thus, one method by which to achieve homogeneity is tomaximize the use of the more hydrophobic, water-insoluble componentslike those that are present in both the digested and deaminated castorprotein, and in the water-insoluble dispersible fraction that can beisolated directly from digested castor (Example 20).

The bond strengths were not significantly affected by pot-life over thetime frame that was evaluated (t=6 minutes to 40 minutes after mixing).

Example 20: Effects of Fractionation and Post-Mix Time on thePerformance of Two-Part Adhesives Prepared with Digested Castor (withand without EVA)

The sample preparation procedures in this Example were identical tothose employed in Example 19. Again, the block shear specimens (SYP)were pressed for 35 minutes using a Carver press with platentemperatures set at 208° C. (6 pairs per cycle).

Two different “Part-A” curative components were used in this Example,including: sample 65-4A-83-1 (from Example 18), and PMDI. The part-Acomponents were each formulated with 0.1 phr FeAcAc.

The Part-B components in this example contained extracts that wereisolated from digested castor as described below.

Digested castor (lot 5-90) was fractionated to yield a water-solublefraction, and a water-insoluble, dispersible fraction. In the firststep, 300 g of digested castor was slurried into 1 liter of distilledwater. The mixture was shaken by hand, and was then placed into asonicator bath for a period of 30 minutes. The slurry then was removedand was allowed to set idle for a period of up to two days to allow theinsoluble portion to settle (in separate experiments, it was found thatcentrifuging was equally adequate). At that point, the clearyellow/amber supernatant was pipetted away and was retained for futureuse. Fresh distilled water was then added to the sediment to bring thetotal volume back to the 1-Liter mark on the container. The process ofshaking, sonicating, settling, supernatant extracting, and replenishingwith fresh distilled water (washing) then was repeated (6 times intotal). In the final step, the water was pipetted from the top of thegrayish-black sediment, and the sediment was then dried in a vacuum ovenat 45° C. Based on the sediment's dry weight, it was determined that thedigested castor was comprised of approximately 50% by weight of thismaterial, the water-insoluble/water dispersible fraction. Separately,the 1^(st) and 2^(nd) supernatants were combined and were then dried toyield a transparent yellow-colored water-soluble fraction.

After drying the fractions, it was verified that the grayish-blacksediment (the water-insoluble and dispersible fraction) could not bere-dissolved in water. On the other hand, the dried supernatant fraction(clear/amber, glassy solid) was completely soluble in water. The twoextracts were separately analyzed by solid state FTIR (see FIGS. 5, 6,and 7). The spectra in FIG. 5 show that carboxylate and amine saltmoieties are primarily associated with the water-soluble fraction. FIG.6 shows that the amide carbonyl stretch band and the amide N—H bend bandare shifted to higher wavenumbers in the water-soluble fraction. Thesecomponents also appear to be present in the water-insoluble dispersiblefraction, but the predominant amide-I and amide-II bands are shifted tolower wavenumbers. Aside from hydrogen bonding effects, thesedifferences also appear to be related to the presence of a higherfraction of primary amide groups in the water-soluble fraction, and to ahigher fraction of secondary amide groups in the water-dispersiblefraction (from the main-chain polypeptide chains). This is corroboratedby the N—H stretching region depicted in FIG. 7.

FIG. 7 shows solid state FTIR spectra of isolated fraction from digestedcastor where the N—H stretching region from FIG. 5 is expanded. Thespectra were vertically scaled to achieve equivalent absorbanceintensities for the secondary amide N—H stretch band centered at 3275cm⁻¹. FIG. 7 shows that the predominant type of amide in thewater-dispersible fraction is the secondary main-chain amide asevidenced by the single, highly symmetric band centered at 3275 cm⁻¹.Although the water-soluble fraction also contains this type of amide, italso contains significantly higher fractions of primary amides asevidenced by the presence of the two primary N—H stretching bands atapproximately 3200 cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹(asymmetric), respectively.

These spectra show that the water-soluble fraction combined a relativelyhigh concentration of primary amides, free carboxylic acids, acid salts,and amine salts. Conversely, the water-insoluble/water dispersiblefraction had a higher fraction of secondary amides. In addition, theamide-I carbonyl absorption band for the water-insoluble/dispersiblefraction was observed to appear at a wavenumber of approximately 1625cm⁻¹, whereas that of the water-soluble fraction was observed atapproximately 1640 cm⁻¹. As will be discussed in other Examples, thisfeature is one of the distinguishing differences between thewater-soluble and water-insoluble fractions; not only for castorproteins, but for soy proteins as well. As this and other Examples show,the most water-resistant two-part adhesives are those prepared withproteins comprising a high percentage of a water-insoluble/waterdispersible fraction, wherein the amide carbonyl stretch of thewater-insoluble/dispersible fraction has a characteristic solid stateFTIR absorption band near 1625 cm⁻¹.

Collectively, the results of this Example show that the digested castorthat was used to prepare the adhesives in prior examples was comprisedof about 50% by weight of an entirely water-soluble fraction, whichitself was comprised of residues containing free carboxylic acids, acidsalts, and amine salts. By virtue of the relatively high concentrationof these moieties, it follows that the digestion process produced arelatively high fraction of water-soluble amino acid species (viapeptide chain-scission). Simultaneously, the digestion process asemployed in the prior examples did not invoke complete backbonehydrolysis. Instead, a water-insoluble, dispersible fraction was alsoformed, which was comprised of a relatively high concentration ofsecondary amides—consistent with the presence of intact,hydrolysis-resistant, main-chain polypeptide units.

In order to prepare two-part adhesives with thewater-insoluble/dispersible extract, a partial vacuum drying method wasemployed to yield an adhesive-ready Part-B component that was comprisedof either the water-insoluble/water dispersible fraction alone, or thesame in combination with EVA. Given that the Part-B component of theseadhesives was water based, the vacuum oven drying process was notcarried through to completion, but instead was stopped when the slurryreached a concentration of about 16% solids by weight. At that point,the water-insoluble/water dispersible fraction remained dispersed inwater, and was ready for direct use as “Part-B” (88-2B) in preparingtwo-part adhesives. This creamy, grey-colored slurry was observed to beshelf-stable for a period of several weeks. It was also discovered thatthe slurry could be readily combined with water soluble polymers, andwith water-dispersible polymer latexes. In this example, the slurry wascombined with an EVA latex (Airflex 426) to yield a latex-modifiedPart-B component (88-1B). An analogous “Part-B” composition was alsoprepared with the dried water-soluble fraction (88-3B). The Part-Bcomponent compositions for this example are given in Table 25.

TABLE 25 88-1B 88-2B 88-3B TP13-1 TP16-1 (weight (weight (weight (weight(weight Part-B composition %) %) %) %) %) Water 79.91 84.04 79.91 83.7968.48 Water-insoluble/ 14.56 15.96 0 16.21 0 dispersible extract fromdigested castor (lot 5-90) Water-soluble 0 0 14.56 0 0 extract fromdigested castor (lot 5-90) Airflex 426 EVA 5.53 0 5.53 0 0 (solidsbasis) Digested castor 0 0 0 0 31.52 % total solids 20.09 15.96 20.0916.21 31.52 % protein 72.47 100.00 72.47 100.00 100.00 (dry basis)

The compositions of the resulting two-part adhesives for this example(Part-A+Part-B) are provided in Table 26 together with average blockshear strengths and wood-failure percentages for SYP block-shearspecimens. Note that in many cases, multiple sample sets weresequentially prepared from the same batch of adhesive as a function oftime so that the pot-life could be evaluated after mixing.

Selected sets of samples were also prepared for boil tests (Table 27).The samples were boiled in water for 2 hours, and were then oven driedfor a period of 24 hours at 65° C. The specimens were then inspected forbondline failure, and were graded as either “P=pass” (no bondlinefailure); “PF=partial bondline failure,” or “F=complete bondlinefailure.”

TABLE 26 B/A ratio Average Time (solids Bond between basis % proteinStrength to Part B mixing and excluding by wt. in % wood SYP (peak loadSample level (g) & Part A Component and pressing volatile cured failureat failure, lbs.) ID type Level (g) (min.) water) adhesive (+/− S.D.)(+/− S.D.) 87-1-1 85-2B; 6.55 g 65-4A-83-1, (1-step synthesis;  6 1.24/146.8  50(40) 3100 (2600) (Ex. 19) 85/15 w/w PMDI/digested castor-lot5-90), 2.0 g 87-1-2 85-2B; 6.55 g 65-4A-83-1, (1-step synthesis; 351.24/1 46.8  70 (25) 4200 (2000) (Ex. 19) 85/15 w/w PMDI/digestedcastor-lot 5-90), 2.0 g 89-1-1 88-1B; 34.34 g 65-4A-83-1, (1-stepsynthesis;  6 1.24/1 46.8  80 (30) 4440 (1700) 85/15 w/w PMDI/digestedcastor-lot 5-90), 5.56 g 89-1-2 88-1B; 34.34 g 65-4A-83-1, (1-stepsynthesis; 40 1.24/1 46.8  97 (4) 5300 (1200) 85/15 w/w PMDI/digestedcastor-lot 5-90), 5.56 g 89-1-3 88-1B; 34.34 g 65-4A-83-1, (1-stepsynthesis; 80 1.24/1 46.8  94 (7) 4650 (620) 85/15 w/w PMDI/digestedcastor-lot 5-90), 5.56 g 89-1-4 88-1B; 34.34 g 65-4A-83-1, (1-stepsynthesis; 24 hours 1.24/1 46.8  20 (20) 1400 (1500) 85/15 w/wPMDI/digested castor-lot 5-90), 5.56 g 90-1-1 88-2B; 15.66 g 65-4A-83-1,(1-step synthesis;  6 min. 1.24/1 62.1  30 (20) 2600 (1500) 85/15 w/wPMDI/digested castor-lot 5-90), 2.02 g 90-1-2 88-2B; 15.66 g 65-4A-83-1,(1-step synthesis; 40 1.24/1 62.1  28 (25) 1800 (1900) 85/15 w/wPMDI/digested castor-lot 5-90), 2.02 g 90-1-3 88-2B; 15.66 g 65-4A-83-1,(1-step synthesis; 80 1.24/1 62.1  70 (20) 2400 (900) 85/15 w/wPMDI/digested castor-lot 5-90), 2.02 g 90-2-1 88-2B; 15.66 PMDI + 0.1%FeAcAc; 2.02 g  6 1.24/1 55.3  30 (30) 2000 (2000) 90-2-2 88-2B; 15.66PMDI + 0.1% FeAcAc; 2.02 g 40 1.24/1 55.3  91 (6) 4250 (1450) 90-3-188-2B NONE N/A N/A 100   3 (4)  700 (700) TP13-1 TP13-1 NONE N/A N/A 100 0  370 (550) TP16-1 TP16-1 NONE N/A N/A 100   5 (5)  820 (1000) TP14-1TP13-1; 16 g PMDI + 0.1% FeAcAc;  5   9/1 90  21 (9) 2940 (440) 0.288 gTP14-2 TP13-1; 16g PMDI + 0.1% FeAcAc; 40   9/1 90  18 (19) 3060 (710)0.288 g TP14-3 TP13-1; 16g PMDI + 0.1% FeAcAc; 80   9/1 90  18 (17) 2620(540) 0.288 g 380-1A 88-1B; 17.17g PMDI + 0.1% FeAcAc;  6 1.24/1 40.1 91 (9) 6500 (1000) (replicate of 2.78 g 91-3-1) 380-1B 88-1B; 17.17gPMDI + 0.1% FeAcAc; 60 1.24/1 40.1  97 (4) 6500 (1200) (replicate of2.78 g 91-3-2) 380-1C 88-1B; 17.17g PMDI + 0.1% FeAcAc; 90 1.24/1 40.1 98 (2) 5900 (1100) (replicate of 2.78 g 91-3-3) 381-1A 88-3B; 17.17 gPMDI + 0.1% FeAcAc; 2.78 g  6 1.24/1 40.1 100 (0) 6000 (500) 381-1B88-3B; 17.17 g PMDI + 0.1% FeAcAc; 2.78 g 60 1.24/1 40.1  91 (15) 5300(750) 381-1C 88-3B; 17.17 g PMDI + 0.1% FeAcAc; 2.78 g 90 1.24/1 40.1 96 (8) 4900(400)

Several observations were made during the mixing of the samples. Inaddition, the data in Table 26 reveal several trends. The bond strengthof the two-part adhesives was generally improved by virtue of removingthe water-soluble components from the digested castor (87-1-1 & 87-1-2vs. 89-1-1 & 89-1-2).

In many cases, the bond strength appeared to improve when the A+Bmixture was aged for some period of time prior to making the block shearspecimens (compare 89-1-1 to 89-1-2 & 89-1-3; compare 87-1-1 to 87-1-2,compare 90-1-1 & 90-1-2 to 90-1-3; and compare 90-2-1 to 90-2-2). Whenthe A+B mixture was aged for too long of a period, the bond strength wasobserved to deteriorate (89-1-3 vs. 89-1-4). Excellent bond strengthswere achieved even when the A+B mixture was aged for 80 minutes prior tothe preparation of block shear specimens (89-1-3). In many cases, thestrength of the adhesive was higher than the cohesive strength of thewood itself.

As observed in prior Examples, the absence of the Part-A curative (i.e.,the use of Part-B alone) resulted in poor bond strength performance(90-3-1 vs. 90-2-2; and TP13-1 vs. TP14-1 through TP14-3).

The effect of aging on bond strength performance was mirrored by boiltest results for several of the sets that were tested. Specifically,boil resistance for three of the sets (those with the highest effectivefractions of water-insoluble/dispersible extract from digested castor)was observed to improve when the A+B mixture was aged for some period oftime prior to making the block shear specimens.

The data in Table 27 show that the water-insoluble/water dispersiblefraction from digested castor can be used to produce adhesives withexcellent bond strengths, and with excellent hydrolytic stability.Moisture resistance was observed to improve with the incorporation ofhigher levels of water-insoluble/dispersible extract from digestedcastor. Thus, in making moisture-resistant adhesives of this type, it ispreferred that the water-insoluble/dispersible fraction be used inexcess of the water-soluble fraction.

During the mixing of the part A and part B components, extremedifferences in homogeneity and dispersion stability were observed.Specifically, the Part-B containing the water-insoluble/dispersibleextract from digested castor (88-1B) formed a homogeneous dispersionimmediately upon mixing (with very little mixing effort), whereas thePart-B containing high levels of water-soluble material (88-2B & 88-3B)required extensive mixing to get even partial dispersion. Mixturescontaining high levels of the water-soluble fraction were unable toaccommodate high levels of the more non-polar PMDI as evidenced by thevisible presence of PMDI droplets within the A+B mixture. Conversely,the A+B mixture made with 88-1B was homogeneous with no evidence of PMDIseparation. Moreover, the mixture was observed to remain stable (with noPMDI phase separation) for a full 24 hours after mixing.

TABLE 27 Boil test results: Average Time P = Pass; Bond between % PF =partial Strength to mixing protein failure; SYP (peak Part B Part A andby wt. in F = complete Comparable % wood load at Sample level (g) &Component and pressing cured bondline sample from failure failure IDtype Level (g) (min.) adhesive failure Table 20-2 (+/− S.D.) (+/− S.D.)91-3-1 88-1B; PMDI + 0.1%  6 40.1 2/6 P; N/A Not tested Not tested 17.17g FeAcAc; 2.78 g 4/6 PF 91-3-2 88-1B; PMDI + 0.1% 60 40.1 6/6 P  N/A Nottested Not tested 17.17 g FeAcAc; 2.78 g 91-3-3 88-1B; PMDI + 0.1% 9040.1 6/6 P  N/A Not tested Not tested 17.17 g FeAcAc; 2.78 g 380-1A88-1B; PMDI + 0.1%  6 40.1 5/6 P; 380-1A  91 (9) 6500 (1000) (replicateof 17.17 g FeAcAc; 2.78 g 1/6 PF 91-3-1) 380-1B 88-1B; PMDI + 0.1% 4540.1 6/6 P  380-1B  97 (4) 6500 (1200) (replicate of 17.17 g FeAcAc;2.78 g 91-3-2) 380-1C 88-1B; PMDI + 0.1% 90 40.1 4/6 P; 380-1C  98 (2)5900 (1100) (replicate of 17.17 g FeAcAc; 2.78 g 2/6 PF 91-3-3) 381-1A88-3B; PMDI + 0.1%  6 40.1  1 P; 381-1A 100 (0) 6000 (500) 17.17 gFeAcAc; 2.78 g 5/6 PF 381-1B 88-3B; PMDI + 0.1% 45 40.1 4/6 PF; 381-1B 91 (15) 5300 (750) 17.17 g FeAcAc; 2.78 g 2/6 F  381-1C 88-3B; PMDI +0.1% 90 40.1 6/6 PF 381-1C  96 (8) 4900 (400) 17.17 g FeAcAc; 2.78 g91-4-1 88-2B; 65-4A-83-1,  6 62.1 6/6 F  90-1-1  30 (20) 2600 (1500)15.66 g (1-step synthesis; 85/15 w/w PMDI/digested castor-lot 5-90),2.02 g 91-4-2 88-2B; 65-4A-83-1, 40 62.1 6/6 F  90-1-2  28 (25) 1800(1900) 15.66 g (1-step synthesis; 85/15 w/w PMDI/digested castor-lot5-90), 2.02 g 90-2-3 88-2B; PMDI + 0.1%  6 55.3 6/6 F  90-2-1  30 (30)2000 (2000) 15.66 FeAcAc; 2.02 g 90-2-4 88-2B; PMDI + 0.1% 90 55.3 2/6P; 90-2-2  91 (6) 4250 (1450) 15.66 FeAcAc; 2.02 g 4/6 PF TP13-2 TP13-1NONE N/A 100 6/6 F  TP13-1  0  370 (550) TP16-2 TP16-1 NONE N/A 100 6/6F  TP16-1  5 (5)  820 (1000)

Example 21: Water-based Glass/Paper Adhesives

This example describes the preparation of several types of adhesives,including:

(1) Pressure sensitive adhesives (PSA)—those that incorporate watersoluble plasticizers like glycerin, or water insoluble plasticizers suchas adipate esters, sebacate esters, citrate esters, etc.;

(2) Water soluble adhesives—those that contain one or more of either adigested protein, a digested and deaminated protein solvated with a base(e.g., triethanolamine, NaOH, sodium carbonate), a water-soluble extractfrom a digested protein, an optional water soluble plasticizer (e.g.,glycerin or 1,2 propane diol), and an optional water soluble polymer(e.g., polyvinylalcohol, poly(vinyl pyrrolidone));

(3) Water-based adhesives (type I)—any of the water-soluble optionsmentioned in items #1 or #2 above with the addition of a water-basedlatex dispersion such as EVA, or with the addition of a waterdispersible protein such as a digested and deaminated protein, or withthe addition of a water-insoluble/water dispersible fraction from aprotein such as digested castor;

(4) Water-based adhesives (type II)—dispersion of one or more in anycombination of a protein derivative such as a digested and deaminatedprotein from castor or whey, a water-insoluble/water dispersiblefraction from any protein including a digested protein, and a latexpolymer;

(5) Crosslinkable adhesives—any of the aforementioned types of adhesives(items #1 through #4) where additional additives are incorporated toimpart crosslinking (e.g., amine-functional additives, acid-functionaladditives, hydroxyl functional additives, anhydride functionaladditives, hydrazine functional additives, isocyanate functionaladditives, organosilanes, and organotitanates).

Adhesives as described above can be formulated to yield physicalproperties ranging from: 1) transparent to opaque; 2) water-soluble toinsoluble; 3) low Tg (below 10° C.) to high Tg (greater than 50° C.); 4)tack-free and glassy to tacky and pressure sensitive. These adhesivesare capable of adhering to multiple substrates including paper, glass,wood, and metals.

In this Example, several formulations were prepared for the purpose oftesting adhesion to glass and paper. Glass microscope slides were wetcoated (via pipette) with a series of water-based adhesive formulationsdescribed in Table 28. In this table, “PVA” refers to poly(vinylalcohol-co-vinyl acetate), 87-89% hydrolyzed; M_(n)=13,000-23,000,obtained from Aldrich Chemical. “AAPS” refers toN-(2-aminoethyl)-3-aminopropyltrimethoxysilane; SIA0591.0, obtained fromGelest, Inc. In some cases, a duplicate set of slides was also prepared,where the adhesive-wetted glass was press laminated with strips ofcorrugated paper in lap-shear type fashion. All samples were dried in agravity oven for approximately 1-hour at approximately 80° C. Thelap-shear specimens were tested for adhesion by hand-tearing the paperfrom the glass, and by determining whether or not the adhesive failed(cohesively or adhesively), and/or whether or not the corrugated paperfailed (cohesively). The results of this experiment are provided inTable 29.

TABLE 28 Digested and Digested Water- Water- deaminated whey solubleinsoluble/ whey protein extract dispersible protein (lot 5-72; fromextract from Airflex-426 (lot 5-75 pH = 6.5 Castor lot Castor lot 5- EVA(% PPD (1,2 from from 5-90 (from 90 (from ID Water PVA Glycerin solidsbasis) propanediol) Example 5) Example 2) Example 20) Example 20) AAPS19-1 90 10 — — — — — — — — 21-1A 89.55 9.95 — — — — — — — 0.5 15-1 88.504.92 — — — 6.58 — — — — 21-1 81.41 9.05 — — — 9.09 — — — 0.45 26-1 81.759.09 — — — — 9.16 — — — 26-2 81.43 9.05 — — — — 9.07 — — 0.45 15-2 82.484.59 — — — 6.13 — — — 6.80 15-3 ^(a)70.84 5.46 12.76 — — 10.94 — — — —14-1 ^(a)81.20 6.26 — — — 12.54 — — — — 21-5 51.61 — — 23.34 — 25.05 — —— — 21-6 — — — — 89.25 9.92 — — — 0.83 88-1B 79.91 — — 5.53 — — — —14.56 — *The water that was used in these samples contained about 5%sodium carbonate; pH = 11.8.

TABLE 29 Sample Adhesive type Characteristics Failure mode(s) 14-1Water-soluble Orange/translucent Cohesive in paper solution; glassyopaque dried film 15-1 Water-based Orange dispersion; Cohesive in paperadhesives glassy opaque (type I) dried film 15-2 Water-based Orangedispersion; Cohesive in paper adhesives glassy dried film (type I);crosslinkable 15-3 Water-soluble Orange/translucent Cohesive in papersolution; soft/ rubbery transparent dried film 21-1 Water-based Orangedispersion; Cohesive in paper adhesives glassy transparent (type I);dried film crosslinkable 21-5 Water-based Light yellow Cohesive in paperadhesives dispersion; tough (type II) transparent dried film 21-6Solution-based; Amber solution; Cohesive in paper crosslinkable glassytransparent dried film 26-1 Water soluble Orange/translucent Cohesive inpaper solution; glassy transparent dried film 26-2 Water soluble;Orange/translucent Cohesive in paper crosslinkable solution; glassytransparent dried film 88-1B (from Water-based Light gray Cohesive inpaper Ex. 20) adhesives dispersion; tough, (type II) opaque dried film

In a second experiment, a group of adhesive-coated glass samples (nopaper) were placed into warm tap water for a period of about 2 hours.The samples were then removed from water, and were evaluated todetermine whether or not the adhesive remained adhered to the glass, andwhether or not the paper remained adhered to the adhesive. The resultsof this experiment are provided in Table 30.

TABLE 30 Solid state composition Soak time Sample (w/w) (min.) Result19-1 100 PVA 30 dissolved 21-1A 95/5 PVA/AAPS 30 dissolved 15-1 57/43Digested and 30 Intact film deaminated whey 60 Intact film protein/PVA90 Broken particulates, delaminated 21-1 48.9/48.7/2.4 30 Intact filmDigested and 60 Intact film deaminated whey 90 Intact filmprotein/PVA/AAPS 26-1 50.2/49.8 Digested 30 dissolved whey/PVA 26-248.84/48.76/2.4 30 dissolved Digested whey/ PVA/AAPS 88-1B 12.5/21.5Water- 30 Intact insoluble/ 60 Intact dispersible 90 intact extract fromCastor/EVA

These results reveal that the best moisture resistance was achieved withsamples containing a high fraction of a water-insoluble/waterdispersible derivatized digested protein. Moisture resistance was alsoenhanced by means of incorporating an aminosilane, which can serve asboth a crosslinking agent and as an adhesion promoter to glass. It isimportant to note that when the more water-soluble digested protein wasused, the resulting adhesive had poor water-resistance, independent ofthe presence or absence of AAPS. This finding mirrors the results thatwere demonstrated in Example 20 for wood adhesives. Specifically, themoisture resistance of wood adhesives was also observed to improve uponremoval of the more water-soluble protein components from the adhesiveformulations. Thus, for applications requiring higher degrees ofmoisture resistance, it is preferable to incorporate awater-insoluble/dispersible protein into the adhesive—either aderivatized type, or an insoluble/dispersible extract from any protein,including a digested protein.

In a third experiment, paper/glass laminates were allowed to soak inwater for a period of about 12 hours at 23° C. The samples were thenremoved from water, and were then evaluated to determine whether or notthe adhesive remained adhered to the glass, and whether or not the paperremained adhered to the adhesive. The results of this experiment areprovided in Table 31.

TABLE 31 Solid state composition Soak time Sample (w/w) (hours.) Result21-1 48.9/48.7/2.4 12 Intact film delaminated Digested and deaminatedfrom the glass and whey protein/PVA/AAPS settled to the bottom with thepaper 21-5 50/50 Digested and 12 Paper and adhesive deaminated whey pro-remained intact and tein/EVA adhered to glass

In a separate experiment, sample 88-2B (from Example 20, Table 25,84.04% water and 15.96% of the water-insoluble/dispersible fraction fromdigested castor), was tested as an adhesive for attaching paper toglass. In this case, the adhesive was allowed to dry at 23° C. (withoutbaking). The protein paste was spread as a thin film on the surface of aglass jar and a piece of paper was then bonded to the surface. The jarwas rolled on a hard surface to allow the adhesive to spread completelyat the interface between the paper and the jar. The jar was then allowedto stand on the bench top for several hours to dry (23° C.).

In order to test moisture durability, the jar was placed in a bath ofwarm water (40° C.). After 15 minutes, the label was peeled and thepaper was observed to cohesively fail while the adhesive layer remainedintact. In addition, it was noted that the adhesive remained bonded tothe glass, and that moderate to hard rubbing was required to remove it.The results of this experiment demonstrate that thewater-insoluble/water dispersible fraction can be used to preparemoisture resistant adhesives for bonding substrates such as paper toglass. Moreover, if desired, these types of adhesives can be comprisedof 100% protein (in the dry state).

In yet another experiment, a water-soluble pressure-sensitive adhesive(PSA) was prepared using the water-soluble fraction from digested castor(formulation 379-1). The dried glassy extract (as described earlier inthis Example) was dissolved in a solution of water and glycerin (5 gramsof the water-soluble extract, 15 grams of water, and 1.75 grams ofglycerin). The translucent solution was deposited onto glass slides.Upon drying, the formulation became transparent and tacky. The adhesivewas tested to determine if it could be used to bond paper to glass. Apiece of notebook paper was cut and pressed onto the surface leaving onecorner free so it could be peeled off. Upon peeling, the failure modewas observed to be partially-cohesive (within the paper), and partiallyadhesive (between the paper and the adhesive). When placed under water,the adhesive readily dissolved away from the glass surface. This resultsillustrates that it is possible to prepare water solublepressure-sensitive adhesives by using the water-soluble extract fromdigested castor together with an appropriate water-soluble plasticizer(glycerin in this case).

If so desired, it is envisioned that moisture resistance could beimparted to this adhesive by means of either crosslinking (using a broadvariety of crosslinking agents such as, amine compounds, silanecompounds, epoxy compounds, or epichlorhydrin-type materials), by meansof using water-insoluble plasticizers, by means of using reactiveplasticizers, or by means of using some combination of these approaches.Further, it is also envisioned that a moisture-resistantpressure-sensitive adhesive could also be prepared by using thewater-insoluble/water dispersible fraction blended in combination with aplasticizer, and/or together with a lower-T_(g) polymer.

Example 22: Two-Part Adhesive Using PMDI with Castor Protein Extractedfrom Castor Meal (No Digestion)

Unlike prior Examples that employed enzyme digested proteins, thisExample shows that enzyme digestion is not always necessary when theobjective is to isolate a water-insoluble/water dispersible fraction. Infact, as this Example demonstrates, the good two-part adhesives (interms of achieving PMDI dispersion, high bond strength, and excellentmoisture resistance) are those that contain a protein containing a highpercentage of a water-insoluble/water dispersible fraction, independentof whether or not the protein is enzyme-digested. The sample preparationprocedures in this example were identical to those employed in Examples19 and 20. Again, the block shear specimens (SYP) were pressed for 35minutes using a Carver press with platen temperatures set at 208° C. (6pairs per cycle).

The part-A components for this Example were formulated with Rubinate-MPMDI containing 0.1 phr FeAcAc. One of the Part-B components for thisexample included a protein that was extracted from castor meal (lot5-94) using a procedure as described below.

Castor meal (4.0 kg containing 24.8% protein) was suspended in 0.1M NaOHat a 10:1 w/w meal to alkali ratio. The suspension was stirred for 18hours at ambient temperature and the solids were then removed bycentrifugation. The supernatant (about 32 liters) was acidified to pH4.5 with 10 N HCl. The protein was allowed to sediment at about 10° C.for 12 hours, the clear supernatant solution was decanted, and the heavyprecipitate (about 2 kg) was collected by centrifugation. The wetprecipitate was freeze-dried yielding 670 g protein isolate.

The water-insoluble and water-soluble fractions were obtained by meansof extraction with water. In the first step, 10 g of the castor proteinisolate (lot 5-94) was slurried into 50 g of distilled water. Themixture was dispersed via mechanical stirring for 2 hours. Aliquots thenwere placed into centrifuge tubes, and the tubes were then spun at 3,400rpm for a period of approximately 35 minutes. The centrifugedsupernatant, which contained the water-soluble fraction, was decantedfrom the remaining water-insoluble sediment, and was poured into aseparate container (this clear yellow supernatant was saved and dried at37° C. for subsequent dispersion experiments and solid state FTIRanalyses). After the first washing step, fresh distilled water was thenadded to the tubes, and the remaining sediment was dispersed into thewater by means of hand-stirring with a spatula. The combinedcentrifugation, decanting, and re-dispersion procedures were performedfor a total of 13 cycles. After the final cycle, the free liquid wasdecanted from the residual paste-like dispersion (the water-insolublefraction from the starting castor protein). Upon drying, the paste wasdetermined to contain 28.58% solids, and the total yield of thewater-insoluble fraction was determined to be 62.87%. Thus, the startingcastor protein itself contained 62.87% water-insoluble material, and37.12% water-soluble material.

In a first experiment, a “Part-B” component was prepared directly withthe freeze dried protein isolate (note that this protein was notdigested). In analogous experiments, Part-B components were alsoprepared with water-insoluble and water-soluble fractions that wereextracted from the castor protein. The “Part-B” compositions are givenin Table 32.

TABLE 32 JM448B1 JM448B2 JM449B1 Part-B Composition (weight %) (weight%) (weight %) Water 77.22 77.22 79.55 Water-insoluble/dispersible 22.780 0 extract from castor protein isolate (5-94) Castor protein isolate(5-94) 0 0 20.45 Water-soluble extract from 0 22.78 0 castor proteinisolate (5-94) % total solids 22.78 22.78 20.45 % natural product (drybasis) 100 100 100

The resulting dispersion of water-insoluble paste (gravimetricallydetermined be 28.58% solids by weight) was mixed with additionaldistilled water to yield a cream containing 22.78% solids, which wasthen used in preparing an adhesive for the present example. The startingdry castor protein (lot 5-94; contained 62.87% water-insolublecomponents and 37.12% water-soluble components) was separately mixedwith water to yield a cream containing 20.45% solids, which was alsoused in preparing an adhesive for the present example (Table 32). Thecompositions of the resulting 2-part adhesives (Part-A+Part-B) areprovided in Table 33 together with average block shear strengths andwood-failure percentages for SYP block-shear specimens. Note that thewater-soluble fraction (JM448B2) was not used to make block shearspecimens because unlike the water-insoluble fraction, the water-solublefraction did not yield a stabilized dispersion of PMDI in water.

Samples were also prepared for a boil test (Table 34). The samples wereboiled in water for 2 hours, and were then oven dried for a period of 24hours at 65° C. The specimens were then inspected for bondline failure,and were graded as either “P=pass” (no bondline failure); “PF=partialbondline failure,” or “F=complete bondline failure.”

The two dried extracts were separately analyzed by solid state FTIR (seeFIGS. 9-11). FIG. 9 shows overlaid solid state FTIR spectra of isolatedfractions from castor protein (lot 5-94), showing an expansion of thecarbonyl amide region. The amide carbonyl stretch band and the amide N—Hbend band are shifted to higher wavenumbers in the water-solublefraction. These components also appear to be present in thewater-insoluble dispersible fraction, but the predominant amide-I andamide-II bands are shifted to lower wavenumbers. Aside from hydrogenbonding effects, these differences appear to be related to the presenceof a higher fraction of primary amide groups in the water-solublefraction. This is corroborated by the N—H stretching region depicted inFIG. 10. Unlike the analogous water-soluble extract from digested castor(FIG. 6), the water-soluble fraction from the castor protein isolate(lot 5-94) appears to contain less carboxylic acid and less amine-saltfunctionality. On the other hand, the water-insoluble extracts from boththe digested castor and the castor protein isolate appear to be verysimilar to one another (see FIG. 11). FIG. 10 shows solid state FTIRspectra of isolated fractions from castor protein (lot 5-94) where theN—H and O—H stretch regions were expanded. The spectra were verticallyscaled to achieve similar absorbance intensities for the secondary amideN—H stretch band centered at 3275 cm⁻¹. FIG. 10 shows that thepredominant type of amide in the water-dispersible fraction is thesecondary main-chain amide as evidenced by the highly symmetric bandcentered at 3275 cm⁻¹. Although the water-soluble fraction also containsthis type of amide, it also contains significantly higher fractions ofprimary amides as evidenced by the breadth of the absorbance regionowing to the presence of the two primary N—H stretching bands atapproximately 3200 cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹(asymmetric), respectively.

Collectively, these spectra revealed that the water-soluble fraction(FIG. 9) was comprised of a relatively high concentration of primaryamines. Conversely, the water-insoluble, dispersible fraction (FIG. 9)was comprised of a higher fraction of secondary amines. Moreover, theamide-I carbonyl absorption band for the water-insoluble/dispersiblefraction was observed to appear at a characteristic wavenumber ofapproximately 1625 cm⁻¹, whereas that of the water-soluble fraction wasobserved at approximately 1640 cm⁻¹ (FIG. 9). As noted previously, thisfeature is one of the distinguishing differences between thewater-soluble and water-insoluble fractions.

The water-insoluble/water dispersible fraction (JM-448B1) was readilycompatible with PMDI (a stable PMDI dispersion was formed when PMDI wasadded to the slurry, and there was no evidence of PMDI phase separation,even after 24 hours). The dispersion of the starting castor protein inwater (JM-449B1), which itself was comprised of a mixture of thewater-soluble and water-insoluble components (the dry castor proteincontained 62.87% water-insoluble components and 37.12% water-solublecomponents), was also readily compatible with PMDI (a stable dispersionwas formed when PMDI was added to the slurry, and there was no evidenceof PMDI phase separation, even after 24 hours). By contrast, a solutioncomprising 22.78% by weight of the water-soluble fraction dissolved inwater (JM-448B2) was unable to form a stable dispersion with PMDI (thisadhesive mixture was JM-450-1; see Table 33). Instead, the PMDI wasobserved to phase separate and coalesce into large droplets that sank tothe bottom of the container.

TABLE 33 Average Bond Time B/A ratio Strength between (solids to SYPmixing basis % protein (peak load Part B Part A and excluding by wt. in% wood at failure, level (g) & Component pressing volatile cured failurelbs) Sample ID type and Level (g) (min.) water) adhesive (+/− S.D.) (+/−S.D.) JM-448-3 JM-448B1; PMDI + 0.1% 55 1.24/1 55.3 90 (10) 5930 7.83 gFeAcAc; 1.435 g  (300) JM-449-3 JM-449B1; PMDI + 0.1% 55 1.24/1 55.3 99(2) 5340 7.83 g FeAcAc; 1.29 g (1010) JM-450-1 JM-448B2; PMDI + 0.1% 551.24/1 55.3 Not tested Not tested 7.83 g FeAcAc; 1.435 g

TABLE 34 Average Boil test Bond results: Strength to Time P = Pass; SYP(peak between % PF = partial % wood load at mixing protein failure;failure failure, lbs.) Part B Part A and by wt. in F = completeComparable (+/− S.D.) (+/− S.D.) level (g) & Component pressing curedbondline sample from from from Sample ID type and Level (g) (min.)adhesive failure Table 33 Table 33 Table 33 JM-448-2 JM-448B1; PMDI +0.1% 55 55.3 6/6 P JM-448-3 90 (10) 5930 7.83 g FeAcAc;  (300) 1.435 gJM-449-2 JM-449B1; PMDI + 0.1% 55 55.3 6/6 P JM-449-3 99 (2) 5340 7.83 gFeAcAc; (1010)  1.29 g

Thus, this Example demonstrates that the ability for the protein todisperse PMDI is dependent upon the presence or absence of thewater-insoluble/water dispersible fraction. Since goodPMDI-dispersability is a prerequisite for the preparation of homogeneousadhesives, the preferred protein for a two-part adhesive system is onewhich contains the water-insoluble fraction at a level which issufficient to emulsify the PMDI dispersion. In order to prepare the bestadhesives (in terms of PMDI dispersibility, bond strength, and moistureresistance), the preferred level of the water-insoluble/waterdispersible fraction within a protein should not be less thanapproximately 10% to 50% by weight of the protein, and more preferablynot less than 50% by weight.

Example 23: Plywood Samples Prepared with Two-Part Castor BasedAdhesives

Plywood samples were prepared from adhesives similar to those describedin Examples 18 through 20. The specific adhesive formulations aredescribed below. The “A” component for each of the adhesives was PMDIwith the FeAcAc catalyst as described previously. The “B” components aregiven in Table 35.

TABLE 35 88-5B 88-6B For Adhesive 391-1 For Adhesive 401-1 Part-Bingredient (weight %) (weight %) Water 65.71 65.07 Digested Castor 28.7528.11 (Lot 5-108) Airflex 426 EVA 5.54 6.82 (solids basis) % totalsolids 34.29 34.93 % protein 83.84 80.48 (dry basis)

Adhesive 391-1 (43.4% active ingredients) was mixed in the followingproportions: Part B (88-5B)=46.98 g of a 31.52% solids digested castorpaste in water (Lot #5-108)+4.53 g Airflex 426 water-based latex (63%solids). Part A=8.34 g PMDI/FeAcAc.

Adhesive 404-1 (50.57% active ingredients) was mixed in the followingproportions: Part B (88-6B)=46.98 g of a 31.52% solids digested castorpaste in water (Lot #5-108)+5.71 g Airflex 426 water-based latex (63%solids). Part A=16.68 g PMDI/FeAcAc.

Plywood Preparation

Plywood samples were prepared using southern yellow pine (SYP) and whitefir (WF) veneers. The veneer thickness was approximately ⅛ inch thickfor both the SYP and WF. 6-inch×6-inch veneer squares were cut (36 sq.in.). The veneers were conditioned to a wood moisture content of 12percent. 7-ply plywood samples were prepared, which equates to 6bond-lines between the veneers.

A net amount of 10.29 grams of “wet” adhesive 391-1 were applied to eachof the six interfaces between the seven veneers (6 bond-lines). Thegrain direction of each ply was alternated by 90 degrees. This amount ofwet adhesive per bondline was applied at an equivalent loading to theamount of wet adhesive that was applied to the 3.5 inch bondline for theblock shear samples as described in previous examples (1 gram wetadhesive per 3.5 sq. in.). In this Example, this equates to a dry weightof approximately 0.12 g/square inch. Plywood Samples 391-1-P (SYP) and391-1F (WF) were prepared by pressing under the same conditions used toprepare the block shear samples. Specifically, 250 psi for 30 minutes ata platen temperature of 208° C. After pressing, the plywood samples weretrimmed to 4 in.×4 in. The resulting SYP plywood had a thickness of 0.5inches and a density of 52 lbs/cu.ft. The WF plywood sample had athickness of 0.5 inches and a density of 48 lbs/cu.ft.

Plywood samples 391-1P and 391-1F were subjected to a 2 hour boil testas described in previous Examples. A 1-inch strip was cut from theplywood sample and subjected to the same conditions as the block shearsamples. All of the plywood samples passed with no evidence ofdelamination between the veneers. The thickness of the boiled plywoodsamples was measured after drying. The dried sample had increased inthickness to 0.75 inches.

A second set of SYP and WF plywood samples were prepared using adhesive404-1. A net amount of 10.29 grams of “wet” adhesive 404-1 were appliedto each of the six interfaces between the seven veneers (6 bond-lines).The grain direction of each ply was alternated by 90 degrees. Thisamount of wet adhesive per bondline was applied at an equivalent loadingto the amount of wet adhesive that was applied to the 3.5 inch bondlinefor the block shear samples as described in previous examples (1 gramwet adhesive per 3.5 sq. in.). In this Example, this equates to a dryweight of approximately 0.14 g/square inch. Plywood samples 404-1P (SYP)and 404-1F (WF) were pressed using the following pressing conditions:150 psi for 10 minutes at a press platen temperature of 140° C. Theseconditions are similar to those used to make hardwood plywood forfurniture applications. The temperature of the center bond-line of the7-ply composite was measures and found to reach a temperature of 90° C.after 10 minutes as can be seen in FIG. 8.

After pressing, the plywood samples were trimmed to 4 in.×4 in. Theresulting SYP plywood had a thickness of 0.93 inches and a density of 34lbs/cu.ft. The WF plywood sample had a thickness of 0.93 inches and adensity of 30 lbs/cu.ft.

Plywood samples 404-1P and 404-1F were also wet tested using the 2-hourboil test. A 1-inch strip was cut from the plywood sample and subjectedto the same conditions as described previously. Each of the plywoodsamples passed with no evidence of delamination between the veneers. Thethickness of a boiled plywood sample was measured after drying. Thedried sample had a thickness to 0.95 inches, very close to the originalplywood thickness of 0.93 inches.

Example 24: Particle Board Samples

Particle board was prepared using 335 grams of SYP saw dust having amoisture content of approximately 12 percent and 67 grams of adhesive404-1 from Example 23. This is a 16.66 percent loading of wet adhesive,which equates to approximately 9.1% percent adhesive on a dry solidscomposite basis (the adhesive itself was comprised of 43.12% digestedcastor, 8.30% EVA, and 48.58% PMDI on a cure-solids basis).

The adhesive was added to the sawdust slowly and mixed with a mechanicalmixer used for kneading dough. After all the adhesive was added, thesample was further mixed and kneaded by hand to insure that the adhesivewas efficiently mixed. A 7-inch×7-inch cardboard frame was centered on a12″×12″×⅛″ stainless steel plate, which was covered with aluminum foil.The sawdust was added slowly into the cardboard frame to try to get auniform density of adhesive coated sawdust particles. After all thesawdust was added, the sawdust was compressed by hand with a 7″×7″×¼″plywood board and the cardboard frame were carefully removed so that theparticle board matte would not be disturbed. The board was removed, apiece of aluminum foil was placed on the particle board matte, andanother 12″×12″×⅛″ stainless steel plate was placed on top. The particleboard was pressed using the following conditions: 150 psi for 10 minutesat a press platen temperature of 140° C.

A strongly bound and densified particle board sample was produced. Thisillustrates the application of this type of adhesive technology forparticle board and medium density fiber board applications. Afterpressing, the particle board was trimmed to 4″×4″ and the sample had athickness of 0.73 inches. The density of the particle board sample wascalculated to be 36.36 lbs/cu. ft. In a subsequent step, a strip was cutfrom the particle board and was boiled for two hours. The sample wasobserved to remain intact, even while saturated with water. The wetsample was then dried in an oven, and was observed to remain intact withno evidence of dismemberment.

Note that the two components of the adhesive (Part-A and Part-B) werepremixed in this Example before being added and blended with the sawdustparticles. Premixing can be accomplished by means of conventionalmethods such as with a paddle mixer or static mixer. The premixedcomponents then can be added to the sawdust via a spray or dripapplication method, followed by rigorous mixing. As an optional method,it is also possible to add each adhesive component to the sawdustsequentially (“sequential addition”) or in tandem (“tandem addition”)without premixing them, and then to rigorously blend the mixture. Theaddition of adhesive components can be accomplished via conventionalmethods include spray and drip methods. Blending can be achieved via anyconventional mixing process including high speed paddle mixing (e.g.,with a Littleford blender or a Henchel-type mixer), sigma-blade mixing,ribbon blending, etc. Optional materials could also be concurrently orsequentially blended with the mixture including fillers such as calciumcarbonate, aluminosilicates, clays fumed silica, nano-sized inorganicparticulates, latex polymers, antimicrobial compounds, etc. Moreover,the viscosity, sprayability, and spreadability of the adhesivecomponents can be controlled by adjusting the amount of water that isadded to the Part-B component before it is premixed with Part-A, or byadding water after the two components have been premixed. In the eventthat premixing is not employed (e.g., if tandem or sequential mixing isemployed), water could be added to the mixture as needed for the purposeof influencing viscosity and sawdust-particle surface coverage.

Example 25. Effects of Fractionation and Post-Mix Time on thePerformance of Two-Part Adhesives Prepared with Digested Soy (with andwithout EVA)

The sample preparation procedures in this example were identical tothose employed in Examples 19 and 20. Again, the block shear specimens(SYP) were pressed for 35 minutes using a Carver press with platentemperatures set at 208° C. (6 pairs per cycle).

The Part-A components for this Example were formulated with Rubinate-MPMDI containing 0.1 phr FeAcAc. The Part-B components in this Examplecontained extracts that were isolated from digested soy (lot 5-81 madevia procedures outlined in Example 7).

Digested soy (lot 5-81) was fractionated to yield a water-solublefraction, and a water-insoluble, dispersible fraction. In the firststep, 300 g of digested soy was slurried into 1 liter of distilledwater. The mixture was shaken by hand, and was then placed into asonicator bath for a period of 30 minutes. Aliquots were placed intocentrifuge tubes, and the tubes were then spun at 3400 rpm for a periodof approximately 35 minutes. The centrifuged supernatant, whichcontained the water-soluble fraction, was decanted off of the remainingwater-insoluble sediment, and was poured into a separate container forlater use (this clear yellow supernatant was placed into an open pan andwas allowed to evaporate dry at a temperature of 37° C.). After thefirst washing step, fresh distilled water was then added to the tubes,and the remaining sediment was dispersed into the water by means ofhand-stirring with a spatula. The combined centrifugation, decanting,and re-dispersion procedures were performed for a total of 5 cycles.After the final cycle, the free liquid was decanted from the residualpaste-like dispersion (yellowish-peach in color). The resultingdispersion (gravimetrically determined be 16.24% solids by weight) wasused in preparing the adhesives for this example.

The dispersion was observed to be stable for a period of several weeks.It was also discovered that the dispersion could be readily combinedwith water-soluble polymers, and with water-dispersible polymer latexes.Moreover, the dispersion was readily compatible with PMDI (a stabledispersion was formed when PMDI was added to the slurry, and there wasno evidence of PMDI phase separation, even after 24 hours). By contrast,neither the water soluble extract from the digested soy, nor thedigested soy itself was capable of stabilizing a dispersion of PMDI inwater.

After drying aliquots of both fractions, it was verified that the yellowsediment (the water-insoluble/dispersible extract) could not bere-dissolved in water. On the other hand, the dried supernatant fraction(clear/yellow solid) was completely soluble in water. The two driedextracts were separately analyzed by solid state FTIR (see FIGS. 12-15).FIG. 13 shows overlaid solid state FTIR spectra of isolated fractionsfrom digested soy, where the N—H region is expanded. The spectra werevertically scaled to achieve equivalent absorbance intensities for thesecondary amide N—H stretch band centered at 3275 cm⁻¹. FIG. 13 showsthat the predominant type of amide in the water-dispersible fraction isthe secondary main-chain amide as evidenced by the single, highlysymmetric band centered at 3275 cm⁻¹. Although the water-solublefraction also contains this type of amide, it also containssignificantly higher fractions of primary amides as evidenced by thepresence of the two primary N—H stretching bands at approximately 3200cm⁻¹ (symmetric) and at approximately 3300 cm⁻¹ (asymmetric),respectively. Collectively, these spectra revealed that thewater-soluble fraction was comprised of a relatively high concentrationof primary amines. Conversely, the water-insoluble, dispersible fractionwas comprised of a higher fraction of secondary amines.

The Part-B component compositions for this Example are given in Table36.

TABLE 36 TP3-1B TP3-2B TP3-3B TP3-4B TP3-5B (weight (weight (weight(weight (weight Part-B Compositions %) %) %) %) %) Water 79.91 83.7679.91 85 68 Water-insoluble/ 14.56 16.24 0 0 0 dispersible extract fromdigested soy (lot 5-81) Water-soluble 0 0 0 15 0 extract from digestedsoy (lot 5-81) Airflex 426 EVA 5.53 0 5.53 0 0 (solids basis) Digestedsoy 0 0 14.56 0 32.00 (lot 5-81) % total solids 20.09 16.24 20.09 15.0032.00 % protein 72.47 100.00 72.47 100.00 100.00 (dry basis)

The compositions of the resulting two-part adhesives for this example(Part-A+Part-B) are provided in Table 37 together with average blockshear strengths and wood-failure percentages for SYP block-shearspecimens. Note that in many cases, multiple sample sets weresequentially prepared from the same batch of adhesive as a function oftime after mixing, so that the pot-life of the 2-part system could beevaluated.

Selected sets of samples were also prepared for boil tests (Table 38).The samples were boiled in water for 2 hours, and were then oven driedfor a period of 24 hours. at 65° C. The specimens were then inspectedfor bondline failure, and were graded as either “P=pass” (no bondlinefailure); “PF=partial bondline failure,” or “F=complete bondlinefailure.”

TABLE 37 Average Bond Time B/A ratio Strength between (solids to SYPmixing basis % protein (peak load Part B Part A and excluding by wt. inat failure, % wood Sample level (g) & Component pressing volatile curedlbs) failure ID type and Level (g) (min.) water) adhesive (+/− S.D.)(+/− S.D.) TP4-1 TP3-1B; PMDI + 0.1%  5 1.24/1 46.8 6270 (740) 100 (0)16 g FeAcAc; 2.592 g TP4-2 TP3-1B; PMDI + 0.1% 40 1.24/1 46.8 6029 (820) 97 (8) 16 g FeAcAc; 2.592 g TP4-3 TP3-1B; PMDI + 0.1% 80 1.24/1 46.85913 (990)  90 (20) 16 g FeAcAc; 2.592 g TP6-1 TP3-3B; PMDI + 0.1%  51.24/1 46.8  553 (980)  7 (11) 16 g FeAcAc; 2.592 g TP6-2 TP3-3B; PMDI +0.1% 40 1.24/1 46.8 3430 (1600)  71 (40) 16 g FeAcAc; 2.592 g TP6-3TP3-3B; PMDI + 0.1% 80 1.24/1 46.8 5690 (640)  93 (6) 16 g FeAcAc; 2.592g TP97-4 TP3-3B; PMDI + 0.1%  5 1.24/1 46.8  180 (160)  3 (3) 16 gFeAcAc; 2.592 g TP8-1 TP3-2B; PMDI + 0.1%  5 1.24/1 55.3 4092 (1063)  84(17) 16 g FeAcAc; 2.095 g TP8-2 TP3-2B; PMDI + 0.1% 40 1.24/1 55.3 4860(830)  70 (20) 16 g FeAcAc; 2.095 g TP8-3 TP3-2B; PMDI + 0.1% 80 1.24/155.3 5080 (830)  98 (4) 16 g FeAcAc; 2.095 g TP9-1 TP3-1B NONE N/A N/A72.47 Samples fell N/A 16 g apart TP11-1 TP3-2B NONE N/A N/A 100 1120(1070)  3 (4) TP12-1 TP3-5B NONE N/A N/A 100  930 (870)  3 (4) TP15-1TP3-2B; PMDI + 0.1%  5   9/1 90 3163 (1360)  21 (18) 16 g FeAcAc; 0.289g TP15-2 TP3-2B; PMDI + 0.1% 40   9/1 90 2770 (1050)  52 (22) 16 gFeAcAc; 0.289 g TP15-3 TP3-2B; PMDI + 0.1% 80   9/1 90 3140 (1300)  73(33) 16 g FeAcAc; 0.289 g

TABLE 38 Average Boil test Bond results: Strength to Time P = Pass; SYP(peak between % PF = partial load at % wood mixing protein failure;failure, lbs.) failure Part B Part A and by wt. in F = completeComparable (+/− S.D.) (+/− S.D.) Sample level (g) & Component pressingcured bondline sample from from from ID type and Level (g) (min.)adhesive failure Table 37 Table 37 Table 37 TP4-4 TP3-1B; PMDI + 0.1%  546.8 3/6 P; TP4-1 6270 (740) 100 (0) 16 g FeAcAc; 3/6 PF 2.592 g TP4-5TP3-1B; PMDI + 0.1% 40 46.8 4/6 P; TP4-2 6029 (820)  97 (8) 16 g FeAcAc;2/6 PF 2.592 g TP4-6 TP3-1B; PMDI + 0.1% 80 46.8 2/6 P; TP4-3 5913 (990) 90 (20) 16 g FeAcAc; 4/6 PF 2.592 g TP6-4 TP3-3B; PMDI + 0.1%  5 46.86/6 F TP6-1  553 (980)  7 (11) 16 g FeAcAc; 2.592 g TP6-5 TP3-3B; PMDI +0.1% 40 46.8 1/6 PF; TP6-2 3430 (1600)  71 (40) 16 g FeAcAc; 5/6 F 2.592g TP6-6 TP3-3B; PMDI + 0.1% 80 46.8 2/6 P; TP6-3 5690 (640)  93 (6) 16 gFeAcAc; 1/6 PF; 2.592 g 3/6 F TP8-4 TP3-2B; PMDI + 0.1%  5 55.3 2/6 P;TP8-1 4092 (1063)  84 (17) 16 g FeAcAc; 2/6 PF; 2.095 g 3/6 F TP8-5TP3-2B; PMDI + 0.1% 40 55.3 1/6 P; TP8-2 4860 (830)  70 (20) 16 gFeAcAc; 3/6 PF; 2.095 g 1/6 F TP8-6 TP3-2B; PMDI + 0.1% 80 55.3 1/6 P;TP8-3 5080 (830)  98 (4) 16 g FeAcAc; 3/6 PF; 2.095 g 1/6 F TP18-1TP3-4B; PMDI + 0.1%  5 55.3 0/6 P; Not N/A N/A 15 g FeAcAc; 2/6 PF;tested  1.81 g 4/6 F TP18-2 TP3-4B; PMDI + 0.1% 40 55.3 1/6 P; Not N/AN/A 15 g FeAcAc; 0/6 PF; tested  1.81 g 5/6 F TP18-3 TP3-4B; PMDI + 0.1%80 55.3 0/6 P; Not N/A N/A 15 g FeAcAc; 0/6 PF; tested  1.81 g 6/6 FTP11-2 TP3-2B NONE N/A 100 6/6 F TP11-1 1120 (1070)  3 (4) TP12-2 TP3-5BNONE N/A 100 6/6 F TP12-1  930 (870)  3 (4)

Like the digested castor extracts of Example 20, the digested soyextracts in this Example also contained water-soluble andwater-insoluble fractions. Moreover, like the analogous digested castorextracts, the best overall combination of bond strengths and waterresistance characteristics were observed when the water-insolublefraction was the primary protein component in the adhesive. In addition,like the water-insoluble digested castor extract, the water-insolubledigested soy extract facilitated the dispersion of PMDI into awater-based medium. A stable dispersion did not form when PMDI was addedto mixtures containing high proportions of the water-soluble extract(including the digested soy itself). In addition, like thewater-insoluble extract from digested castor, the water-insolubleextract from digested soy was itself readily dispersible in water, andwas similarly comprised of a relatively high concentration of secondaryamides—consistent with the presence of a relatively high fraction ofintact, hydrolysis-resistant, main-chain polypeptide units. Moreover,the amide-I carbonyl absorption band for the water-insoluble/dispersiblefraction was observed to appear at a wavenumber of approximately 1625cm⁻¹, whereas that of the water-soluble fraction was observed atapproximately 1640 cm⁻¹. As noted earlier, this feature is one of thedistinguishing differences between the water-soluble and water-insolublefractions; not only for castor proteins, but for soy proteins as well.

Importantly, and as shown in FIG. 12, the amide carbonyl stretch bandand the amide N—H bend band are shifted to higher wavenumbers in thewater-soluble fraction. These components also appear to be present inthe water-insoluble dispersible fraction, but the predominant amide-Iand amide-II bands are shifted to lower wavenumbers. Aside from hydrogenbonding effects, these differences appear to be related to the presenceof a higher fraction of primary amide groups (and/or primary amines) inthe water-soluble fraction (from lower molecular weight amino acidfragments), and to a higher fraction of secondary amide groups in thewater-dispersible fraction (from the main-chain polypeptide chains).This is supported by the N—H stretching region depicted in FIG. 13.

FIG. 13 shows that the predominant type of amide in thewater-dispersible fraction is the secondary main-chain amide asevidenced by the single, highly symmetric band centered at 3275 cm⁻¹.Although the water-soluble fraction also contains this type of amide, italso contains significantly higher fractions of primary amides(presumably from amino acid fragments) as evidenced by the presence ofthe two primary N—H stretching bands at 3200 cm⁻¹ (symmetric) and atapproximately 3300 cm⁻¹ (asymmetric), respectively.

In spite of being derived from different plant sources, thewater-insoluble dispersible fractions from digested soy and digestedcastor are spectrally similar to one another (FIG. 14). Conversely, thewater-soluble fractions appear to have different spectralcharacteristics (FIG. 15). The comonality between the two types ofwater-soluble fractions is that they both appear to contain primaryamines/amides, a feature consistent with the presence of lower molecularweight peptide chains and amino acid fragments.

Example 26: Two-Part Adhesives Comprising PMDI with a Water-InsolubleExtract from Soy Flour

The sample preparation procedures in this Example were the same as thoseused in Example 25. Again, the block shear specimens (SYP) were pressedfor 35 minutes using a Carver press with platen temperatures set at 208°C. (6 pairs per cycle).

The part-A components for this Example were formulated with Rubinate-MPMDI containing 0.1 phr FeAcAc. The Part-B components in this exampleincluded soy flour (Prolia™ PDI-90 de-fatted soy flour from Cargill),and a water-insoluble extract that was isolated from the soy flour. Notethat the soy flour used in this example was reportedly comprised ofapproximately 50-54% protein by weight. The soy flour was not digestedprior to use.

The soy flour was fractionated to yield a water-soluble fraction, and awater-insoluble/water dispersible fraction. In the first step, 300 g ofsoy flour was slurried into 1 L of distilled water. The mixture wasshaken by hand, and was then placed into a sonicator bath for a periodof 30 minutes. Aliquots were placed into centrifuge tubes, and the tubeswere then spun at 3400 rpm for a period of approximately 35 minutes. Thecentrifuged supernatant, which contained the water-soluble fraction, wasdecanted off of the remaining water-insoluble sediment, and was pouredinto a separate container. Fresh distilled water was then added to thetubes, and the remaining sediment was dispersed into the water by meansof hand-stirring with a spatula. The combined centrifugation, decanting,and re-dispersion procedures were performed for a total of (15) cycles.After the final cycle, the free liquid was decanted from the residualpaste-like dispersion (yellowish in color; gravimetrically determined tocontain 10.25% solids by weight). The resulting dispersion was thenmatted with adsorbent paper towels to achieve a total solids content ofapproximately 18%. Distilled water was then added to adjust the solidslevel to 15.96% for use in the adhesive.

After drying aliquots of both fractions, it was verified that thesediment (the water-insoluble/water dispersible fraction) could not bere-dissolved in water. On the other hand, the dried supernatant fraction(clear/yellow solid) was completely soluble in water. In addition, itwas also discovered that the water-insoluble/water dispersible fractioncould be readily combined with water-soluble polymers, and withwater-dispersible polymer latexes. Moreover, the dispersion was readilycompatible with PMDI (a stable dispersion was formed when PMDI was addedto the slurry, and there was no evidence of PMDI phase separation, evenafter 24 hours). By contrast, neither the water soluble extract from thesoy flour, nor the soy flour itself was capable of stabilizing adispersion of PMDI in water.

The Part-B component composition for this example is given in Table 39.

TABLE 39 JM-B1 Part-B ingredient (weight %) Water 84.04Water-insoluble/dispersible extract from soy flour 15.96% % total solids15.96% % natural product (dry basis) 100

The composition of the resulting two-part adhesive for this example(Part-A+Part-B) is provided in Table 40 together with average blockshear strengths and wood-failure percentages for SYP block-shearspecimens. The samples were boiled in water for 2 hours, and then wereoven dried for a period of 24 hours at 65° C. The specimens wereinspected for bondline failure, and were graded as either “P”=pass (nobondline failure), “PF”=partial bondline failure, or “F”=completebondline failure. Boil test results are provided in Table 41.

TABLE 40 Time B/A ratio between (solids Average Bond mixing basis %protein Strength to Part B Part A and excluding by wt. in % wood SYP(peak load Sample level (g) & Component pressing volatile cured failureat failure, lbs) ID type and Level (g) (min.) water) adhesive (+/− S.D.)(+/− S.D.) JM-442-1 JM-B1; PMDI + 0.1% 40 1.24/1 55.3 88 (15) 5550(1390) 7.83 g FeAcAc; 1.01 g

TABLE 41 Average Bond Strength to Time SYP (peak between % % wood loadat mixing protein failure failure, lbs.) Part B Part A and by wt. inComparable (+/− S.D.) (+/− S.D.) Sample level (g) & Component pressingcured Boil test sample from from from ID type and Level (g) (min.)adhesive results: Table 26-2 Table 26-2 Table 26-2 JM-445-1 JM-B1;PMDI + 0.1% 6 55.3 5/6 P; N/A Not tested Not tested 7.83 g FeAcAc; 1/6PF 1.01 g JM-445-2 JM-B1; PMDI + 0.1% 40 55.3 6/6 P JM442-1 88 (15) 5550(1390) 7.83 g FeAcAc; 1.01 g

As shown in FIG. 18, the comonality between the insoluble extracts fromseveral different protein samples is that they all appear to containabsorption bands that are consistent with the presence of a specifictype of secondary amide functionality. Importantly, the amide-I carbonylstretch band and the amide-II N—H band are shifted to lower wavenumbersthan the analogous absorption bands from their water-solublecounterparts. As noted earlier, the best performing two-part adhesives(i.e., those that are the most water resistant, those that mostefficiently disperse PMDI in water, and those that exhibit the highestbond strength to wood) are those prepared with proteins comprising ahigh percentage of a water-insoluble/water dispersible fraction, whereinthe amide carbonyl stretch of the water-insoluble/water dispersiblefraction has a characteristic solid state FTIR absorption band nearapproximately 1625 cm⁻¹.

More specifically, as illustrated by FIG. 18, it is desirable that thewater-insoluble/water dispersible fraction have a characteristic amide-Iabsorption band between approximately 1620 cm⁻¹ and 1632 cm⁻¹, and anamide-II band between approximately 1514 cm⁻¹ and 1521 cm⁻¹. Inaddition, it is also desirable that the water-insoluble/dispersiblefraction contain a prominent 2° amide N—H stretch absorption bandcentered at approximately 3275 cm⁻¹. Proteins with these spectralcharacteristics are likely to exhibit the beneficial attributes thathave been illustrated throughout the multiple Examples provided herein.

Example 27: Two-Part Adhesives Using PMDI with Digested Castor and SoyProteins

This Example demonstrates the use of three types of digested samples inpreparing two-part adhesive systems with PMDI. The three types ofdigested materials included: (1) digested whole castor meal (lot 6-9);(2) the water-insoluble fraction from digested castor protein inwet-paste form (lot 6-10-1); and (3) the water-insoluble fraction fromdigested soy protein in wet-paste form (lot 6-10-2). The proteinpreparation procedures are given below:

(1) Lot 6-9. Digested Whole Castor Meal:

Castor meal (100 g, 40% protein) was blended with minimal amount ofwater (350 mL). NaOH (5 N, 4.4 mL) was added to bring the pH to 9.0.Calcium chloride was added to final concentration in water of 10 mMfollowed by Everlase® (0.2 g; in other words 2 g enzyme/Kg protein). Thereaction was stirred by a mechanical stirrer for 4 hours at 55° C.,cooled to room temperature, and the pH was lowered to 4.0 by theaddition of concentrated HCl. The product was a viscous homogeneouspaste (22.35% solids).

(2) Lot 6-10-1. Water-Insoluble Fraction from Digested Castor Protein inWet-Paste Form:

Purified Castor Protein (25 g; lot #5-94—see Example 22) was suspendedin water (250 mL). Calcium chloride was added to the final concentrationof 10 mM and the pH was brought to 9.0 by addition of 5N NaOH. Everlase®(0.4 g; in other words 16 g enzyme/Kg protein), and the suspension wasstirred at 55° C. for 4 hours. The reaction was cooled to ambienttemperature; and the pH was adjusted to 4.0 by the addition ofconcentrated HCl. The reaction was maintained at a temperature of 8-10°C. for approximately 12 hours. The precipitate was removed bycentrifugation at 15,000×g for 15 minutes; and it then was re-suspendedin water (250 mL), and re-precipitated under the same conditions. Theresulting wet-paste was collected without drying, and was labeled:Castor protein digest (water-insoluble fraction). The yield wasapproximately 32%, and the resulting paste was gravimetricallydetermined to contain 24.91% solids. The enzyme to protein ratio for6-10-1 differed from that which was used in preparing lot 5-83 (Example6) and lot 5-90 (Example 18).

(3) Lot 6-10-2. Water-Insoluble Fraction from Digested Soy Protein inWet-Paste Form:

Soy Protein (25 g) was suspended in water (250 mL). Calcium chloride wasadded to the final concentration of 10 mM, and the pH was brought to 9.0by addition of 5N NaOH. Everlase® (0.4 g; in other words 16 g enzyme/Kgprotein) was added and the suspension was stirred at 55° C. for 4 hours.The reaction was cooled to ambient temperature; and the pH was adjustedto 4.0 by the addition of concentrated HCl. The reaction was maintainedat a temperature of 8-10° C. for approximately 12 hours. The precipitatewas removed by centrifugation at 15,000×g for 15 min; and then it wasre-suspended in water (250 mL), and re-precipitated under the sameconditions. The resulting wet paste was collected without drying, andwas labeled: Soy protein digest (insoluble fraction). The yield wasapproximately 39%, and the resulting paste was gravimetricallydetermined to contain 22.57% solids. Note that the type of enzyme usedand the enzyme to protein ratio for 6-10-2 differed from that which wasused in preparing lot 5-81 (Example 7).

Each of the wet paste dispersions was observed to be stable for a periodof several weeks. It was also discovered that the dispersions could bereadily combined with water-soluble polymers, and with water-dispersiblepolymer latexes.

The preparation procedures for the two-part adhesives and block shearspecimens in this example were identical to those employed in Examples19 and 20. Again, the block shear specimens (SYP) were pressed for 35minutes using a Carver press with platen temperatures set at 208° C. (6pairs per cycle). The part-A components were formulated with Rubinate-MPMDI containing 0.1 phr FeAcAc. The Part-B components included the threeaforementioned digested protein pastes (the compositions are provided inTable 42). For comparative purposes, the percent solids of the wetpastes were adjusted to a level of 15.96% by adding distilled water.

TABLE 42 % Solids in Sample Number Part B Sample Description the SampleJM-438-1 water-insoluble fraction 15.96% from digested castor pro- teinin wet-paste form; Lot # 6-10-1 JM-438-2 water-insoluble fraction 15.96%from digested soy pro- tein in wet-paste form; Lot # 6-10-2 JM-438-3digested whole castor 15.96% meal in wet-paste form; Lot # 6-9 TP88-2B(from Example 20) Water-insoluble fraction 15.96% isolated from drieddigested castor (lot 5-90) TP3-2B (from Example 25) Water-insolublefraction 16.24% isolated from dried digested soy (lot5-81)

The compositions of the resulting 2-part adhesives for this example(Part-A+Part-B) are provided in Table 43 together with average blockshear strengths and wood-failure percentages for SYP block-shearspecimens. For comparative purposes, the compositions of the resultingtwo-part mixtures (Part-A+Part-B) were identical to those used in aprevious example (see sample TP-90-2-2 and TP-90-2-1 in Example 20). Twosample sets were sequentially prepared from the same batch of adhesiveso that the pot-life of the 2-part system could be evaluated (at t=6minutes, and at t=40 minutes after mixing).

In addition, the dispersion characteristics of the two-part mixtures(Part-A+Part-B) were qualitatively evaluated upon mixing. The dispersioncharacteristics were qualitatively compared to those that were achievedwith the water-insoluble extracts that were separately isolated fromdried digested castor (sample TP90-2-1 & TP90-2-2 from Example 20), andfrom dried digested soy (TP8-1 & TP8-2 from Example 25). Each of the wetpastes was observed to be compatible with PMDI, but to varying degrees.

In the best cases, the PMDI was observed to readily disperse with nosign of phase separation. Examples of these types of adhesiveformulations included the following:

TP90-2-1 (water-insoluble fraction isolated from dried digested castorlot 5-91),

TP90-2-2 (water-insoluble fraction isolated from dried digested castorlot 5-91),

TP8-1 (water-insoluble fraction isolated from dried digested soylot5-81),

TP8-2 (water-insoluble fraction isolated from dried digested soylot5-81),

JM441-1 (digested whole castor meal in wet-paste form; Lot #6-9), and

JM441-2 (digested whole castor meal in wet-paste form; Lot #6-9).

In the other cases, a higher degree of mechanical agitation was requiredto achieve PMDI dispersion, and in some cases, the PMDI showed evidenceof partial phase separation and coalescence. These types of samplesincluded:

JM439-1 & JM439-2 (water-insoluble fraction from digested castor proteinin wet-paste form; Lot #6-10-1), and

JM440-1 & JM440-2 (water-insoluble fraction from digested soy protein inwet-paste form; Lot #6-10-2).

In spite of these differences, it was still possible to prepare SYPblock-shear specimens. However, the best bond strengths were observedfor the protein samples that exhibited the greatest ability tofacilitate the dispersion of PMDI into water.

TABLE 43 Average Bond Time B/A ratio Strength between (solids to SYPmixing basis % protein (peak load Part B Part A and excluding by wt. inat failure, % wood level (g) & Component pressing volatile cured lbs)failure Sample ID type and Level (g) (min.) water) adhesive (+/− S.D.)(+/− S.D.) JM-439-1 JM-438-1; PMDI + 0.1% 6 1.24/1 55.3  480 (1450)  8(5) 15.66 g FeAcAc; 2.02 g JM-439-2 JM-438-1; PMDI + 0.1% 40 1.24/1 55.3 790 (1250)  8 (10) 15.66 g FeAcAc; 2.592 g JM-440-1 JM-438-2; PMDI +0.1% 6 1.24/1 55.3  570 (500)  1 (2) 15.66 g FeAcAc; 2.02 g JM-440-2JM-438-2; PMDI + 0.1% 40 1.24/1 55.3 1012 (1400)  5 (8) 15.66 g FeAcAc;2.592 g JM-441-1 JM-438-3; PMDI + 0.1% 6 1.24/1 55.3 4030 (1630) 63 (34)15.66 g FeAcAc; 2.02 g JM-441-2 JM-438-3; PMDI + 0.1% 40 1.24/1 55.34790 (1390) 65 (12) 15.66 g FeAcAc; 2.592 g 90-2-1 (from 88-2B; PMDI +0.1% 6 1.24/1 55.3 2000 (2000) 30 (30) Example 20) 15.66 g FeAcAc; 2.02g 90-2-2 (From 88-2B; PMDI + 0.1% 40 1.24/1 55.3 4250 (1450) 91 (6)Example 20) 15.66 g FeAcAc; 2.02 g TP8-1 TP3-2B; PMDI + 0.1% 5 1.24/155.3 4092 (1063) 84 17)   16 g FeAcAc; 2.095 g TP8-2 TP3-2B; PMDI + 0.1%40 1.24/1 55.3 4860 (830) 70 (20)   16 g FeAcAc; 2.095 g

Example 28: Mass Spectrometric Analysis of Protein Fractions

This Example describes a characterization of the various protein samplesdescribed herein via MALDI Mass Spectrometry using an Ultraflex IIIinstrument from Bruker.

The instrument was set in positive mode, in order to detect positiveions generated during the ionization process. The voltage applied toaccelerate the ion into the TOF analyzer was set at 25 KV. The analysiswas carried out by using the instrument in reflection mode whichimproves the resolution. Solid samples were dissolved in DMSO at aconcentration of 10 mg/mL. Water-soluble supernatant fractions whichwere solvated in water.

Each sample solution was mixed with a matrix solution (for analyticalpurposes). The matrix was an inert compound of low molecular weightwhich absorbs at the same wavelength of the laser, Nd:YAG 355 nm. Thematrices used were: α-CHCA, alpha-cyano-4-hydroxycinnamic acid,dissolved in a solution of ACN/H₂O (70:30) with 0.1% of TFA at aconcentration of 10 mg/mL; and DCTB,T-2-[3-(4-t-Butyl-phenyl)-2-methyl-2-propenylidene]malononitrile,dissolved in THF at a concentration of 10 mg/mL. The first matrix wasmainly used for the analysis of peptides and proteins while the secondone, DCTB, was suitable for the analysis of polymers.

The matrix solutions and the sample solutions were mixed at a 10:1volume ratio respectively. For the analysis where DCTB was used asmatrix, NaTFA (10 mg/mL in THF) was added to the solution matrix/sampleas a cationizing agent at a ratio 10:2:1 by volume (matrix:sample:salt,respectively). 0.8 μL of the resulting solutions were spotted on atarget plate made of polished steel, and only after the solvents werecompletely dried was the target loaded into the instrument. The spectrawere collected and manipulated by using FlexAnalysis software releasedby Bruker Daltonics.

Relative fragment intensities were normalized and used to calculatenumber average (Mn), weight average (Mw), and z-average (Mz) molecularweight parameters for various samples. The results are summarized inTable 44.

TABLE 44 Sample ID Mn Mw Mz Mw/Mn Castor protein isolate lot 5-94 11491162 1179 1.01 Digested castor lot 5-83 951 1081 1250 1.13 DigestedCastor lot 5-108 897 1011 1169 1.12 Digested Castor Water-insoluble/1009 1371 1928 1.35 dispersible fraction (lot 5-108) Digested CastorWater-soluble 1532 1697 1894 1.10 fraction (lot 5-108) Soy ProteinIsolate 2023 2104 2161 1.03 Digested Soy (lot 5-81) 894 989 1104 1.10Digested Soy Water-insoluble/ 910 1119 1512 1.22 dispersible fraction(lot 5-81) Digested Soy Water-soluble 837 888 941 1.06 fraction (lot5-81)

The results indicate that the molecular weight characteristics (asdetermined by MALDI mass spectroscopy) of the polypeptide compositioncan depend on the process used to obtain the polypeptide composition.For example, castor protein isolate was observed to have a higher numberaverage molecular weight than its digested counterpart. Further, upondigestion, the number average molecular weight was observed to decreasewhile the polydispersity increased. The same trend was observed for thesoy protein isolate and its digested counterpart.

Other experimental results indicate that proteins in the water-solublepolypeptide composition from digested castor have a higher numberaverage molecular weight than its parent protein isolate. However,proteins in the water-soluble polypeptide composition from digested soyhad a lower number average molecular weight than its parent soy proteinisolate.

Collectively, these results indicate that it is possible to preparecompositions that both i) have particular molecular weight features, andii) have the ability to disperse an oil in water or water in oil, byselecting a particular procedure for preparing the polypeptidecomposition.

Example 29: Two-Part Adhesives Using PMDI with Polypeptide-ContainingDispersions Obtained by Extracting Whole Castor Meal

This Example demonstrates the use of two types of extracted, whole,non-digested castor meal samples in preparing two-part adhesive systemswith PMDI. The two types of extracted materials included: (1)non-digested whole castor meal obtained from Kopco Oil Products, Rajkot,India extracted under basic conditions using a 1.0% sodium hydroxidesolution; and (2) non-digested whole castor meal obtained from Kopco OilProducts, Rajkot, India extracted under neutral conditions with water.The protein preparation procedures are as follows:

(1) Basic Condition Preparation:

100 grams of ground castor meal was added to 500 mL of a 1.0% sodiumhydroxide solution having a pH of 13.35 at 22° C. The materials werestirred under ambient conditions (22° C.) for two hours. The pH wasmeasured to be 13.03 at the end of the reaction. The pH was lowered to4.0 by the addition of 1.0 N HCl. The product was a viscous homogeneouspaste having a solids content of approximately 13.42%.

(2) Neutral Condition Preparation:

100 grams of ground castor meal was added to 500 mL of distilled waterhaving a pH of 5.45 at 22° C. The materials were stirred under ambientconditions (22° C.) for two hours. The pH was 5.68 at the end of thereaction. The product was a viscous homogeneous paste having a solidscontent of approximately 16.66%.

The castor meal preparations described above were fractionated to yielda water-soluble fraction, and a water-insoluble/water dispersiblefraction. Aliquots of each preparation were placed into centrifugetubes, and the tubes then were centrifuged at 3400 rpm for a period ofapproximately 35 minutes. The centrifuged supernatant, a clear solutionwhich contained the water-soluble fraction, was decanted off of theremaining water-insoluble sediment. Fresh distilled water then was addedto the tubes, and the remaining sediment was dispersed into the water bymeans of hand-stirring with a spatula. The combined centrifugation,decanting, and re-dispersion procedures were performed for a total of(5) cycles. After the final cycle, the free liquid was decanted. For thecase where the meal was extracted under basic conditions, the remainingwater-insoluble/dispersible extract (a paste-like dispersion) had asolids content of approximately 25.98% (additional water was added toadjust the solids level to 15%). The water-insoluble extract from theneutral preparation had a solids content of approximately 15%. Analogouspaste-like dispersions also were separately prepared with thenon-fractionated, whole castor meal that was extracted with water underneutral conditions, and with the non-fractionated whole castor meal thatwas extracted under basic conditions. It is important to note that eachof the polypeptide-containing dispersions also contained residualcellulosics and carbohydrate components that were inherent to the wholeplant-based meal. Each of the dispersions was mixed with PMDI at a ratioof 1.24/1 (w/w) solids to PMDI for the purpose of testing PMDIdispersability in water.

The two dispersions containing the water-insoluble/dispersiblefractions, (obtained under basic and neutral extraction conditions,respectively), were compared to the analogous dispersions that wereprepared with extracted whole meal (these samples were not fractionated,and implicitly contained both the water-soluble and water-insolublefractions). The dispersion characteristics of the two-part mixtures(Part-A=PMDI+Part-B=the water-based polypeptide dispersion) werequalitatively evaluated upon mixing using procedures described inExample 26 and 27. The results are provided in Table 45.

TABLE 45 Whole meal extraction Description of polypeptide PMDI Sampleconditions composition Dispersibility JM-453-1-A Basic Extracted,non-fractionated Does not whole meal containing both disperse PMDIwater-soluble and water- insoluble, dispersible fractions JM-453-1-BBasic Extracted, fractionated Disperses whole meal containing PMDIwater-insoluble/water dispersible fraction JM-454-1-A Neutral Extracted,non-fractionated Does not whole meal containing both disperse PMDIwater-soluble and water- insoluble/water dispersible fractionsJM-454-1-B Neutral Extracted, fractionated Disperses whole mealcontaining PMDI water-insoluble dis- persible fraction

Each of the fractionated polypeptide-containing dispersions (solelycomprised of the water-insoluble/water dispersible fraction togetherwith other residual plant-based components) was observed to yield astable emulsion of PMDI in water. These mixtures were desirable for useas two-part adhesives. Conversely, the non-fractionatedpolypeptide-containing dispersions (comprised of the additionalwater-soluble fraction) were unable to disperse PMDI in water.

Example 30: Particle Board Composites Prepared with Adhesive BindersComprising Water-Insoluble/Dispersible Polypeptide-Containing FractionsDerived from Whole Castor Meal (Under Basic Conditions)

The water-insoluble/water dispersible polypeptide-containing compositionfor this Example was prepared under basic conditions (followed by acidaddition) using the materials and procedures as outlined in Example 29.Whole castor meal (from Kopco Oil Products, Rajkot, India) was dispersedin a 1.0% sodium hydroxide solution, and was then mixed with a 1 NormalHCl solution to a final pH value of approximately 4 to 5. The dispersionthen was centrifuged and washed with water (at pH approximately 6 to 7)to remove the water soluble components (yielding a paste-like slurrycomprising approximately 16% solids by weight). The 16% solids slurrywas used (at various dilutions) to disperse PMDI in water for thepurpose of preparing two-part adhesive binders for the manufacture ofparticle board composites. Several adhesive compositions were preparedusing a range of protein/PMDI ratios, and using a range of slurrydispersion concentrations as described in Table 46.

TABLE 46 Percent solids in Part-B Part-B Weight PMDI Protein-containing(% water-insoluble/dispersible Percent (Part-A) fraction/ Adhesivepolypeptide-containing (liquid Weight PMDI ratio Sample fraction byweight in water) dispersion) Percent (solids basis) JM505-1 10 84.745815.2542 0.5556 JM505-2 16 80.1924 19.8076 0.6478 JM505-3 8 83.958916.0411 0.4187 JM505-4 12 89.1359 10.8641 0.9846 JM505-5 16 87.197412.8026 1.0897 JM505-6 10 84.7458 15.2542 0.5556 JM505-7 10 89.877910.1221 0.8879 JM505-8 11 89.8156 10.1844 0.9701 JM505-9 16 91.39788.6022 1.7000

As noted in prior Examples, water-insoluble/water dispersiblepolypeptide-containing fractions, like their more purified counterparts,are capable of dispersing oils in water, as long as one of thecomponents of the mixtures includes a water-insoluble/water dispersiblepolypeptide fraction that when isolated, has the ability to disperse oilin water (see Example 34), and has specific solid state FTIR absorptioncharacteristics (as described in FIG. 18 and in Example 26). Thewater-insoluble/dispersible polypeptide-containing fraction as preparedin this example was observed to disperse PMDI in water for each of theformulations described in Table 46.

The formulations in Table 46 were used to prepare particle boardcomposites using the mixing and pressing procedures as outlined inExample 24. The wet adhesives were mixed with the wood particles atvarious ratios to yield composite compositions as described in Table 47.Samples from each of the resulting composites were subjected to boilingwater for two hours (as described in Example 24), and were observed toremain completely intact, even after oven drying.

TABLE 47 Parts of Liquid % Binder % PMDI % PMDI by Adhesive Mixed byweight by weight weight of the with 100 parts in the cured in the curedtotal binder Sample of Wood composite composite composition JM505-114.9333 3.4222 2.2000 64.3 JM505-2 11.2344 3.5370 2.1466 60.7 JM505-314.7179 3.2409 2.2844 70.5 JM505-4 14.4608 3.0235 1.5235 50.4 JM505-515.6466 4.0179 1.9227 47.9 JM505-6 14.9333 3.4222 2.2000 64.3 JM505-713.9615 2.5987 1.3765 52.9 JM505-8 15.4782 3.0120 1.5289 50.8 JM505-920.4665 4.5378 1.6807 37.0

These formulations demonstrate the preparation of moisture-resistantcured particle board composites containing a total binder level rangingfrom approximately 2.5% by weight to 4.5% weight of the cured composite,where the binder includes a water-insoluble/water dispersiblepolypeptide fraction or a water-insoluble/water dispersiblepolypeptide-containing fraction and a PMDI fraction with an optionalcatalyst. The PMDI comprises from about 30% to about 70% (w/w) of thecured binder. The PMDI fraction comprises from about 1.3% to about 2.3%(w/w) of the cured composite. Particle boards prepared with these typesof binder compositions are uniquely capable of withstanding boilingwater and hence are extremely moisture resistant.

In the event that moisture-resistance is not a requirement for theend-use application, cured composites can also be prepared with a totalbinder level of less than about 5% by weight of the cured composite,wherein the binder includes a water-insoluble/water dispersiblepolypeptide fraction or a water-insoluble/dispersiblepolypeptide-containing fraction and a PMDI fraction with an optionalcatalyst. The PMDI fraction optionally comprises from about 0.05% toabout 2.5% by weight of the cured composite.

The level of water that may be used to disperse the ingredients and tofabricate a composite can be adjusted for the specific application byvirtue of controlling the % solids in the Part-B component, the weightratio of the Part-B solids ingredients to PMDI, and the total binderlevel in the finished composite (on a solids basis). Depending on thelevel of water that is required to fabricate the composite, the % solidsin the Part-B component can range from about 5% to about 30% by weightsolids, or from about 9% to about 20% by weight solids. Similarly, thePart-B solids to PMDI weight ratio can range from approximately 20:1 to1:20, and more preferably from about 10:1 to 1:10; and the totalpercentage of binder in the cured composite (on a solids basis)preferably can range from about 1% to about 15% by weight of the curedcomposite, and more preferably can range from about 2% to about 10% byweight.

Example 31: Particle Board Composites Prepared with Adhesive BindersComprising Water-Insoluble/Dispersible Polypeptide Fractions Derivedfrom Whole Castor Meal Under a Combination of Basic and AcidicConditions

The polypeptide composition for this Example was prepared according tothe procedure provided below.

Materials: (1) Castor meal (Jayant Agro-Organics Limited, Mumbai,India); moisture 12% max, ash 12% max, acid insoluble ash+oil 3% max,protein 50% minimum; (2) tap water (municipal source); (3) 50/50 (w/w)NaOH concentrate in water; (4) Muriatic acid (37% w/w HCl in water) fromChem Central, CAS 7647-01-0; 4) PPG 400 polypropylene glycol, Mn=400,Aldrich Chemical, CAS #253-22-69-4.

A 60-gallon capacity batch reactor (equipped with a stir mixer) wascharged with 240.2 pounds of a 0.978% (w/w) solution of NaOH in water.The reactor temperature was monitored throughout the course of thereaction and was observed to remain constant at approximately 21° C.Then, 47.1 pounds of castor meal was dispersed into the reactor whilestirring. The pH was checked after 10 minutes of mixing and wasdetermined to be 13. The reaction was allowed to proceed for 1 hour. Theviscosity was qualitatively observed to increase during this time, andthe pH was observed to remain constant (pH 13).

After approximately 1 hour of mixing under basic conditions, 33 poundsof acidic solution (1.2 M HCl) was added to the reactor. The pH wasobserved to be 11.5 (at this point, the total addition of HCL was 17.46moles, which resulted in partial neutralization of the original 26.648moles of NaOH). After approximately 10 minutes of mixing, an additional71 pounds of the 1.2 M HCl was added, and the pH was observed todecrease to a value of 1.3 (this represented an incremental addition of37.57 moles of HCl, for a cumulative addition of 55.03 moles). At thispoint in the reaction, the mole ratio of HCl to NaOH was approximately2.06/1. The dispersion was mixed under acidic conditions forapproximately 30 minutes. Then, 14 pounds of a 10% (w/w) NaOH solutionin water was added to the reactor which represented an incrementaladdition of 15.875 moles of NaOH (for a cumulative total addition of42.523 moles NaOH). The net cumulative additions of HCl and NaOH equatedto a molar ratio of HCl/NaOH=1.29/1 to yield a final pH of 4.4. Then,the slurry was collected by passing it through a 1 micron meshfiberglass filter bag. The filtrate was washed with copious amounts ofmunicipal tap water (at pH approximately 6 to 7) for the purpose ofremoving a large proportion of the water-soluble protein fraction. Thewashing was continued until the yellow mother-liquor solution(water-soluble extracts) was observed to become water-white and clear.The resulting dispersion (water-insoluble fraction) was gravimetricallydetermined to contain approximately 19.3% solids.

Finally PPG 400 (Aldrich Chemical, CAS 253-22-69-4) (33.6 g of PPG 400in 7.9 pounds of water was added to 38.5 pounds of the concentratedpaste from step 6 (comprising 7.43 pounds solids+31.07 pounds water).The resulting slurry contained 7.43 pounds of water-insoluble/waterdispersible protein-containing components, approximately 0.074 lbs. ofPPG 400 (0.99% by weight protein solids), and 38.97 lbs. water. Thepercent solids of the resulting paste-like slurry was gravimetricallydetermined to be approximately 16% by weight (15.987% by weightwater-insoluble/water dispersible polypeptide-containing extract plus0.16% by weight PPG 400).

The 16% solids slurry was used (at various dilutions) to disperse PMDIin water for the purpose of preparing two-part adhesive binders for themanufacture of particle board composites. Several adhesive compositionswere prepared using a range of protein/PMDI ratios, and using a range ofslurry dispersion concentrations as described in Table 48.

TABLE 48 Percent solids in Part-B Part-B Weight PMDI Protein-containing(% water-insoluble/dispersible Percent (Part-A) fraction/ Adhesivepolypeptide-containing (liquid Weight PMDI ratio Sample fraction byweight in water) dispersion) Percent (solids basis) TPEX32-2 16 80.1919.81 0.65 TPEX32-5 16 87.19 12.80 1.09 TPEX32-9 16 91.39 8.60 1.70TP12-22-09-1 9 92.32 7.68 1.08 TP12-22-09-8 12 89.27 10.73 1.00

The water-insoluble/water dispersible polypeptide-containing fraction asprepared in this Example was observed to disperse PMDI in water for eachof the formulations described in Table 48.

The formulations in Table 48 were used to prepare particle boardcomposites using the mixing procedures as outlined in Example 24. Thepressing conditions for curing the composites were similar to those usedin Example 24. Each of the samples was pressed using a platentemperatures of 205° C. for a total press time of 15 minutes. In onecase, an additional sample (TPEX32-2) was pressed at the same platentemperature for a total press time of 3.3 minutes. Thermocouples wereplaced into the composites during the press cycle for the purpose ofmonitoring the actual bulk composite temperature. These data revealedthat the actual composite temperature reached 100° C. at t=3 minutes,and remained steady at approximately 105° C. until t=10 minutes, atwhich point the temperature slowly increased to a maximum of about 118°C. (by the end of the longest press cycle at t=15 minutes).

The wet adhesives were mixed with the wood particles at various ratiosto yield the cured composite compositions as described in Table 49.Samples from each of the resulting composites were subjected to boilingwater for two hours (as described in Example 24), and were observed toremain completely intact, even after oven drying. Even the sample thatwas pressed for a press time of 3 minutes remained intact (sampleTPEX32-2).

TABLE 49 Parts of Liquid % Binder % PMDI % PMDI by Adhesive Mixed byweight by weight weight of the with 100 parts in the cured in the curedtotal binder Sample of Wood composite composite composition TPEX32-211.23 3.54 2.15 60.7 TPEX32-5 15.65 4.02 1.92 47.7 TPEX32-9 20.47 4.541.68 37.0 TP12-22- 12.76 2.00 0.96 48.0 09-1 TP12-22- 12.41 2.59 1.3050.2 09-8

These formulations demonstrate the preparation of moisture-resistantcured particle board composites containing a total binder level rangingfrom approximately 2% by weight to 4.5% weight of the cured composite,wherein the binder includes a water-insoluble/water dispersiblepolypeptide-containing fraction and a PMDI fraction, wherein the PMDIcomprises between approximately 10% and 65% by weight of the curedbinder, and wherein the PMDI fraction comprises between approximately0.9% and 2.2% by weight of the cured composite. Particle boards preparedwith these types of binder compositions are uniquely capable ofwithstanding boiling water and hence are extremely moisture resistant.Similarly moisture resistant composites can be prepared with a totalbinder level ranging from approximately 1.2% by weight to 2.5% weight ofthe cured composite, wherein the binder comprises awater-insoluble/water dispersible polypeptide-containing fraction and aPMDI fraction, and wherein the PMDI fraction comprises betweenapproximately 0.3% and 1.1% by weight of the cured composite.

Example 32: Particle Board Prepared with Adhesive Binders ComprisingOptional Polymer Latex Together with Water-Insoluble/DispersiblePolypeptide Fractions Derived from Whole Castor Meal (Combination ofBasic and Acidic Conditions)

Particle board composites were prepared using PMDI together with thesame water-insoluble/water dispersible polypeptide-containingcomposition that was employed in Example 31 (16% solids dispersion). Inaddition, an EVA latex/emulsion polymer was used to demonstrate thatbinder compositions can be optionally prepared with additionalcomponents/additives. One particular advantage of latex polymers is thatthey facilitate the preparation of Part-B dispersions with higherpercentages of dispersed solids ingredients. This can serve the purposeof reducing the amount of water that is required during the fabricationof composites, while simultaneously maintaining equivalent or reduceddispersion viscosities, and equivalent or higher binder levels in thecured composites. The disadvantage of many latex polymers is that theyare incapable of dispersing PMDI in water by themselves. However, when alatex polymer is combined with a water-insoluble/water dispersiblepolypeptide-containing dispersion, the materials work together to yielddispersions that not only have higher percentages of dispersed solids atequivalent or lower viscosities, they also exhibit the unique ability tostabilize PMDI dispersions in water. This PMDI-stabilization function isuniquely facilitated by the presence of the water-insoluble/dispersiblepolypeptide-containing composition.

The various formulations used in this Example are set forth in Table 50.The combination of the EVA latex with the water-insoluble/dispersiblepolypeptide-containing fraction facilitated the formation of stable PMDIdispersions in water (macroscopic phase separation of PMDI was notobserved, even after the mixtures were allowed to set for periods of upto one hour under static conditions). Samples JM539-8 and JM541-1 wereprepared with PMDI that contained 0.1 phr of iron acetylacetonatecatalyst.

TABLE 50 Percent total solids in Part-B (% water- Wet weight insoluble/of water- (EVA+ dispersible insoluble/ Part-B Total Protein polypeptide-dispersible Weight % fraction)/ containing polypeptide- Wet (protein-PMDI PMDI fraction plus % containing weight containing (Part-A) ratioAdhesive EVA by weight dispersion of EVA dispersion + Weight (solidsSample in water) (12% solids) latex EVA latex) Percent basis) JM-539-217.1 81.94 9.10 91.04 8.96 1.74 (TP12-22-09-2) JM539-5 20.0 81.41 15.1596.56 3.44 5.61 (TP12-22-09-5) JM-539-8 12.0 89.28 0 89.28 10.72 1.00(TP12-22-09-8) JM-541-1 15.0 84.41 5.28 89.69 10.31 1.31 (TP12-22-09-1)

The formulations in Table 50 were used to prepare particle boardcomposites using the mixing procedures as outlined in Examples 24 and31. The pressing conditions for curing the composites were similar tothose used in Examples 24 and 31. Each of the samples was pressed usinga platen temperature of 205° C. for a total press time of 15 minutes.The wet adhesives were mixed with the wood particles at various ratiosto yield the cured composite compositions as described in Table 51.

TABLE 51 % Parts of polypeptide Liquid containing % PMDI Adhesive % PMDIfraction by % EVA % total by weight % EVA by Mixed wt. in wt. in by wt.in binder in of the weight of the 100 parts cured cured cured curedtotal binder total binder % water Sample of Wood composite compositecomposite composite composition composition addition JM-539-2 12.99 1.131.24 0.72 3.09 36.51 23.39 9.5 (TP12- 22-09-2) IM539-5 12.65 0.42 1.201.17 2.79 15.14 41.93 9.5 (TP12- 22-09-5) JM-539-8 12.41 1.30 1.29 02.59 50.0 0 9.5 (TP12- 22-09-8) JM-541-1 13.53 1.35 1.33 0.44 3.12 43.3713.99 10.0 (TP12- 22-09-1)

Samples from each of the resulting composites were subjected to boilingwater for two hours (as described in Example 24), and were observed toremain completely intact, even after oven drying. The densities of theresulting composites after boiling are provided in Table 52.

TABLE 52 Density Density Sample (g/cu. cm) (lb/cu. Ft) JM-539-2(TP12-22-09-2) 0.3858 24.09 JM539-5 (TP12-22-09-5) 0.3770 23.54 JM-539-8(TP12-22-09-8) 0.3852 24.05 JM-541-1 (TP12-22-09-1) 0.3753 23.43

These formulations demonstrate the preparation of moisture-resistantcured particle board composites containing a total binder level rangingfrom about 2.5% to about 3.1% by weight of the cured composite, whereinthe binder comprises a water-insoluble/water dispersible polypeptidefraction or a water-insoluble/water dispersible polypeptide-containingfraction, an optional polymer latex fraction, and a PMDI fraction withoptional catalyst. The PMDI comprises from about 5% to about 65% byweight of the cured binder and from about 0.3% to about 2% by weight ofthe cured composite. The optional polymer latex is an EVA latex polymercomprising from about 0% to about 45% by weight of the cured binder andfrom about 0% to about 1.2% by weight of the cured composite.

Particle boards prepared with these types of binder compositions arecapable of withstanding boiling water and hence are extremely moistureresistant. Similarly moisture resistant composites can be prepared witha total binder level ranging from about 1.2% to about 2.5% by weight ofthe cured composite. The binder comprises a water-insoluble/waterdispersible polypeptide fraction or a water-insoluble/water dispersiblepolypeptide-containing fraction, an optional polymer latex fraction, anda PMDI fraction with optional catalyst. The PMDI fraction comprises fromabout 0.1% to about 1.1% by weight of the cured composite.

Similar formulation considerations also apply to the fabrication andmanufacture of plywood composites. For example, moisture-resistant curedplywood assemblies can be laminated with bondline adhesive levelsranging from approximately 0.008 pounds/ft.² up to approximately 0.056pounds/ft.², wherein the adhesive comprises awater-insoluble/dispersible polypeptide-fraction or awater-insoluble/dispersible polypeptide-containing fraction, an optionalpolymer latex fraction, and a PMDI fraction with an optional catalyst.The PMDI comprises between approximately 20% and 70% by weight of thecured adhesive. The optional polymer latex is an EVA latex polymercomprising from about 0% to about 45% by weight of the cured binder. Itis expected that plywood composites prepared with these types ofadhesive compositions will be capable of withstanding boiling water andhence will be extremely moisture resistant.

Although the EVA latex used in this Example effectively increased the %solids of the Part-B component, other types of additives can be used aswell, including water-dispersible types as well as water-soluble typesof additives. Water soluble additives can include hydroxyl-functional oramine-functional compounds that are capable of reacting with PMDI suchas glycerin, urea, propylene glycol, polypropylene glycol, polyethyleneglycol, trimethylol propane and its adducts, etc.; and the water-solublepolypeptide fractions that are obtained via the process set forth inFIG. 2. The maximum tolerable level of a water-soluble polypeptidefraction will be dictated first by the resulting dispersion stability ofthe curative (e.g., PMDI), and secondly by the resulting moistureresistance of the composite (as dictated by end-use requirements).

It is contemplated that it is possible to use mixtures ofwater-insoluble/water dispersible polypeptide or polypeptide-containingcompositions that have been derived from different plant sources (e.g.,mixtures derived from different plant sources such as soy, canola, andcastor, and in any combination).

Example 33: Dispersion of Oil in Water with an IsolatedWater-Insoluble/Water Dispersible Protein Fraction from Digested SoyProtein

The protein materials for this Example were the same as those that wereused in Example 25. Several of the previous Examples demonstrated theunique ability of a water-insoluble/water dispersible polypeptidefraction to disperse PMDI in water. In order to demonstrate thegenerality of this finding, an oil-in-water dispersion was prepared witha water-insoluble/water dispersible polypeptide composition that wasisolated from a digested soy protein. The isolated water-dispersiblefraction was dispersed in water at a level of 16.59% solids, and 1 gramof the resulting paste-like dispersion was weighed into a small glassvial. Then, 0.2 grams of Castrol Syntec, 5W-50 motor oil was added, andthe mixture was stirred with a spatula. The resulting mixture was a veryhomogenous cream. The cream was still homogeneous after one hour. In thenext step, an additional 0.3 grams of motor oil was added to bring thetotal amount of motor oil to 0.5 grams. The viscosity increasedslightly, but the mixture remained very homogeneous. The sample waschecked 15 days after mixing and no phase separation was observed. Bycontrast, neither the water soluble extract from the digested soy, northe digested soy itself was capable of stabilizing a dispersion of theoil-in-water.

Example 34: Dispersion of Oils in Water Using a Water-Insoluble/WaterDispersible Polypeptide Composition

This Example further demonstrates that a water-insoluble/waterdispersible polypeptide fraction can be used to disperse a broadspectrum of oils in water.

A water-insoluble/water dispersible polypeptide fraction was isolatedfrom enzyme digested castor (lot 5-108) using the isolation proceduresas reported in Example 20 (the procedure for enzyme digestion is givenin Example 6). The MALDI fragmentation molecular weight characteristicsof the isolated fraction are provided in Example 28 (Table 44). Thesolid state FTIR spectroscopic absorption characteristics for theisolated water-insoluble/dispersible polypeptide fraction conform withthose as described in FIGS. 6, 7, 9, 10, 11, 14, 16, 18, 19, 20, and 21(amide-I absorption range: 1620-1632 cm⁻¹; amide-II absorption range:1514-1521 cm⁻¹). Solution state two-dimensional proton-nitrogen coupledNMR characteristics for the isolated water-insoluble/dispersiblepolypeptide fraction conform with those as described in Example 38 (twoprotonated nitrogen clusters enveloped by ¹⁵N chemical shift boundariesat approximately 86.2 ppm and 87.3 ppm; and with ¹H chemical shiftboundaries at approximately 7.14 and 7.29 ppm for the first cluster; andat approximately 6.66 and 6.81 ppm for the second cluster).

Surprisingly, water-insoluble/water dispersible polypeptide fractionswith these spectral characteristics (unlike their water solublecounterparts) exhibit the unique ability to emulsify and stabilizedispersions of oil in water and water in oil. This unique oil-dispersingcapability is observed with water insoluble/water dispersiblepolypeptide compositions that are extracted and isolated from multiplesources, including but not limited to (1) whole meals orprotein-isolates from either soy, canola, or castor that are extractedof their water-soluble polypeptide components at or near pH-neutralconditions; (2) whole meals or protein-isolates from soy, canola orcastor that are subjected to base catalyzed hydrolysis followed by acidaddition and subsequent extraction of water-soluble polypeptidecomponents; (3) whole meals or protein-isolates from soy, canola orcastor that are subjected to acid catalyzed hydrolysis followed by baseaddition and subsequent extraction of their water-soluble polypeptidecomponents; (4) whole meals or protein-isolates from soy, castor, orcanola that are subjected to combinations of base catalyzed hydrolysiswith enzyme digestion followed by acid addition and subsequentextraction of water-soluble polypeptide components.

It is understood that the stabilization of an oil-in-water orwater-in-oil emulsion/dispersion depends on several factors, includingbut not limited to the presence or absence of a stabilizing entity suchas a surfactant or a dispersant; the nature of the oil (i.e., itspolarity, hydrophilicity, hydrophobicity, solubility parameter, etc.);the nature of the surfactant or dispersant (i.e., HLB value, chargecharacteristics, molecular weight, water solubility, oil solubility,etc.); the ionic strength of the water-phase; the presence or absence ofadditives and impurities in either the oil or water phases; theconcentration of the oil (i.e., its weight percent in water); and theconcentration of the stabilizing entity. It is further understood thatthe efficiency of a stabilizing entity (a “stabilizing entity” being adispersant, an emulsifier, a surfactant, or thewater-insoluble/dispersible polypeptide composition of the presentinvention) is often judged according to its ability stabilize anemulsion for some specified period of time (i.e., to prevent themacroscopic phase separation of immiscible oil and water componentsunder shear or under static conditions).

In the present invention, the water insoluble/water dispersiblepolypeptide composition is most efficient when it is isolated in itspurest form (i.e., it is capable of stabilizing the most oil in waterwhen it is fractionated from protein-isolates or from digested proteinisolates as noted above, where substantially all of the water-solublecomponents and non-protein components have been removed). However,stable oil-in-water or water-in-oil dispersions can be facilitated whenthe water-insoluble/water dispersible polypeptide composition are mixedwith impurities, including water soluble components (e.g., water-solubleprotein fractions), and non-protein based components (e.g., sugars,cellulosics) such as those that may be present in extracts obtained fromdigested or partially digested whole meals (see Examples 26, 30, 33, and37).

Several of the previous Examples demonstrated the unique ability of awater-insoluble/dispersible polypeptide fraction to disperse PMDI inwater. In order to further demonstrate the generality of this finding,several oil-in-water dispersions were prepared with awater-insoluble/water dispersible polypeptide composition that wasisolated from a digested castor protein. The water-insoluble/waterdispersible fraction was isolated as a paste-like dispersion in water.The paste was diluted with water to 16% solids, and separately to 14%solids. In the next step, 3-gram aliquots of each paste were separatelyweighed into 15 mL plastic beakers. Next, aliquots of the oils shown inTable 53 were separately added to individual paste aliquots at a ratioof 1 part oil to 1 part solid water-insoluble/water dispersiblepolypeptide composition on a weight basis (20 mixtures in total). Themixtures were stirred by hand with a spatula, and were observed to formhomogenous creams. The creams remained homogeneous with no visible signsof macroscopic phase separation for prolonged periods of time aftermixing including periods ranging from 1 minute after mixing, 5 minutesafter mixing, 10 minutes after mixing, 15 minutes after mixing, 30minutes after mixing, 1 hour after mixing, and 2 hours after mixing. Bycontrast, the analogous water-soluble extract from the digested castorwas incapable of stabilizing dispersions of the oils in water.

TABLE 53 Oil type Source PMDI Rubinate-M from Huntsman CorporationMineral oil Drakeol 35 from Penreco Soybean oil RBD from ADM ProcessingCo. Motor oil Castrol Syntec, 5W-50 Castor oil Pale Pressed Castor Oilfrom Alnor Oil Company, Inc. Dibutyl Phthalate 99% from Acros Epoxidizedsoybean oil From Aldrich Caprylic triglyceride Neobee M-5 from StepanCo. Eucalyptus oil From Aromas Unlimited Tributyl o-acetylcitrate 98%from Aldrich

The unique ability for the water-insoluble/water dispersible polypeptidecomposition to stabilize dispersions of oil-in-water or water-in-oil isnot only useful in adhesive applications, it is useful for anyapplication where dispersion stabilization is important including oilrecovery operations (e.g., oil spills, crude oil drilling andsubterranean sequestering), cosmetics applications, pharmaceuticalapplications, food applications, polymer additive applications, andpolymer processing applications.

The above list of oils is not intended to be limiting. Instead, it isintended to illustrate the general ability of the water-insoluble/waterdispersible polypeptide fraction to stabilize emulsions of water-in oilor oil-in water. As such, it is contemplated that many other types ofoils not included in this list can be similarly emulsified andstabilized in water with a stabilizing entity comprising the preferredwater-insoluble/water dispersible polypeptide fraction of the presentinvention.

Protein compositions not enriched for the water-insoluble/waterdispersible fractions are unable to disperse oils. For example, a 16%solids dispersion of soy protein isolate, Lot 5-81, (Soy protein isolateSOLPRO 958® Solbar Industries Ltd, POB 2230, Ashdod 77121, Israel;protein content approximately 90%) was prepared by adding 32 grams ofsoy protein isolate to 168 grams of water at a pH of approximately 4 to6 (JM-570-1). Seven 10 gram aliquots of JM-570-1 were weighed into 20 mLdisposable beakers. A 10 gram aliquot contained 1.6 grams of soy proteinisolate and 8.4 grams of water. Seven different oils (namely, PMDI,mineral oil, soybean oil, motor oil, castor oil, dibutyl phthalate andepoxidized soybean oil, see Table 53) were added separately at a w/wratio of 1 part oil to 1 part protein solids (1.6 grams oil was added toeach 10 gram aliquot). The mixtures were stirred by hand with a spatula.None of the oils was observed to be dispersible in the 16% solidsdispersion of the soy protein isolate.

In a separate experiment, the soy protein isolate was washed with water(pH approximately 6 to 7) and was centrifuged to remove and discard thesupernatant (the water-soluble polypeptide fraction). The remainingpaste-like slurry (the water-insoluble/water dispersible polypeptidefraction; about. 16% solids in water) was then used in an analogousexperiment to disperse the same oils. All of the oils were successfullydispersed at a 1/1 w/w ratio of oil to solids with no visible sign ofmacroscopic phase separation. This demonstrates that the waterinsoluble/water dispersible polypeptide fraction can be isolated fromsoy protein isolate after washing to remove the water soluble component.

Example 35: Thermoplastic Compositions Comprising Water-Insoluble/WaterDispersible Polypeptide Fractions Derived from Digested Castor

This Example illustrates the use of a water-insoluble/water dispersiblepolypeptide composition in preparing thermoplastic materials. In sodoing, a water-insoluble/water dispersible polypeptide fraction can beused alone (isolated and dried) or in combination with other materials.In one experiment, a dried powder of a water-insoluble/water dispersiblepolypeptide-containing composition (enzyme digested castor) was used toprepare a thermoplastic blend with polyvinylchloride (PVC).

The digested castor was prepared as described in Example 6 (it containedapproximately 50/50 w/w of the water-insoluble/water dispersiblepolypeptide faction together with a water soluble fraction). Althoughthermoplastic blends can conceivably be prepared by one of many methods(e.g., melt blending via extrusion, dry-blending followed by Banburymixing, calendering, etc.), the unique ability for thewater-insoluble/water dispersible fraction to disperse in oil proved tobe advantageous in preparing a plastisol, so a plastisol-processingapproach was used in the present illustration.

The formulations shown in Table 54 were mixed to yield stable liquidplastisol-dispersions. Small 6.5 g aliquots of the dispersions wereweighed into aluminum pans, and were subsequently fused at 180° C. for15 minutes in a static gravity oven to yield solid, flexiblethermoplastic pucks.

TABLE 54 Material 25-1 25-2 25-3 PVC (Geon 120, series 120 × 400, DP =1270) 100 100 100 Dibutylphthalate (DBP, Acros) 80 80 181 Epoxidized soyoil (ESO, Aldrich) 8 8 1.23 Calcium Stearate/Zinc Stearate (separatelyfrom 2 2 0.77 Aldrich, blended 50/50 w/w) Digested Castor lot 5-110C 300 100

In a second experiment, an isolated and dried water-insoluble/waterdispersible polypeptide fraction (extracted and dried from digestedcastor with water-soluble components removed) was mixed with glycerin ata weight ratio of approximately 1/1 to yield a powdered dry blend.Powdered dry-blends of this type can conceivably be prepared with otherliquids, including but not limited to plasticizers such asdibutylphthalate and tributylyacetylcitrate, propanediol, polypropyleneglycol, soy oil, castor oil, linseed oil, and the like. Once formed, adry blend of this type can conceivably be used in a number of ways tofabricate material objects, films, sheets, etc. The dry blends canconceivably be pelletized, thermoformed, and/or blended with othermaterials to fabricate various objects for a variety of uses.

In the present Example, the dry blend comprising approximately 50/50(w/w) glycerin with the water-insoluble/dispersible polypeptide fractionwas subsequently mixed with water at a 0.5/1 (w/w) ratio to yield aliquid dispersion. The dispersion then was coated onto a glass slide,and was then oven dried at 150° C. for 17 minutes to yield a film. Theresulting translucent film was observed to be tough and moistureresistant.

In another experiment, a 1/1 (w/w) dry-blend of glycerin with thewater-insoluble/dispersible polypeptide fraction was spread separatelyonto a glass slide and onto aluminum foil, and was then baked in an ovenat 150° C. for 30 minutes. The resulting films were observed to betranslucent, rigid, and moisture resistant.

Example 36: Fiberglass Composites Prepared from a Water-Insoluble/WaterDispersible Polypeptide-Containing Fraction Derived from Whole CastorMeal

The adhesives of the present invention can be used as binders for thepreparation of fiber mats as well as reinforcing binders for fibercomposites.

In this Example, fiberglass composites were prepared using PMDI togetherwith the same water-insoluble/water dispersible polypeptide-containingcomposition that was employed in Example 31 (16% solids dispersion inwater derived from castor meal). The polypeptide-containing compositionwas diluted with water (pH 6 to 7) from 16% solids to 12% solids, andwas then blended with PMDI to yield the homogeneously dispersedcomposition TP12-22-09-8 (see Table 48 in Example 31).

A 50 g quantity of chopped E-glass fiber strands (Advantex™ 983-10Csized E-glass from Owens Corning, 10-13 micrometer diameter, chopped to4 mm nominal length) was weighed into a plastic beaker. Next, 58.3 g ofbinder formula TP12-22-09-8 was blended with the strands using a spatulato yield a thick paste, and then the mixture was gently kneaded by handto achieve thorough wetting of the fibers. The resulting mixture wasnominally comprised of 50 parts by weight glass fiber, 6.25 parts byweight PMDI, 6.25 parts by weight of the water-insoluble/dispersiblepolypeptide-containing composition, and 45.8 parts water (thetheoretical binder content in the cured composite was targeted to be 20%by weight). The mixture was removed from the beaker and was matted byhand over an 8 square-inch section of silicone treated release paper.The wet mat (approximately 3 mm thick) was covered with a second pieceof silicone coated release paper, and was then pressed in a Carver pressfor a dwell time of 10 minutes using platen temperatures of 200° C., and700 pounds pressure (approximately 11 psi).

The cured composite was qualitatively observed to be rigid and tough(average thickness=0.018 cm, approximate density=7 to 10 g/cm³). Inorder to illustrate the moisture resistance of the composite, a 2.5 gsample of the mat was placed into a 30 mL beaker of water and was soakedfor a period of seven days at 23° C. There was no visual evidence ofdisintegration/deterioration over the entire test period. Moreover, whenthe sample was removed from the water, it was observed to remain intactand qualitatively tough/rigid. The sample was blotted dry with a papertowel and was observed to weigh approximately 2.9 g within half an hourof removal from the water, and it returned to its original weight within6 hours.

In a second experiment, a laminated wood composite was prepared by meansof laminating 3″×3″ sections of the cured fiberglass mat from thepresent example (noted above) to both sides of a 3″×3″ particle boardspecimen that was prepared with the same TP12-22-09-8 binder composition(sample number JM539-8, containing 2.59% binder by weight as describedin Example 32, Table 50). Formulation TP12-22-09-8 was also used as theadhesive to adhere the fiberglass composite mat sheets to both faces ofthe particle board. Approximately 2.5 g of the wet adhesive compositionwas spread over each surface of the particle board, and a curedfiberglass mat sheet was affixed to each side. The 3-layer constructionwas pressed in a Carver press for a dwell time of 10 minutes underapproximately 1100 pounds of pressure (approximately 122 psi) withplaten temperatures set at 205° C.

The resulting laminated composite was qualitatively observed to be flat,and dimensionally stable after soaking in water for 24 hours at 23° C.Laminated composites of this type can be used in constructionapplications where dimensional stability and moisture resistance areimportant (e.g., flooring).

In addition to the type of laminated composite noted above, it is alsopossible to prepare composites comprising mixtures of fibers with othermaterials. One particularly useful example of this type of compositeincludes a particle board composite comprising adhesives of the presentinvention as the binder (e.g., formula TP12-22-09-8) wherein a fractionof the wood furnish (ranging from about 0.1% to 10% by weight) isreplaced with other types of fibers (e.g., glass fibers as used in thisexample). Although the particle board as described in prior examplesalready has superior dimensional stability when compared to conventionalboards prepared with conventional UF and PF binders, the incorporationof other types of fibers can improve the dimensional stability to aneven greater degree, thereby facilitating the creation of compositeswith even higher degrees of moisture resistance. It is contemplated thatsuch composites would be particularly useful in flooring, roofing,countertops, and in other applications requiring superior moistureresistance. Composites of this type (with or without fiberreinforcement) may also be compression molded during the curing step toform dimensional impressions so as to render them useful in applicationssuch as siding, paneling, flooring tiles, wall tiles, etc.

Example 37: Adhesives Derived from Canola Meal

The water-insoluble/water dispersible polypeptide-containing compositionfor this Example was prepared under basic conditions (followed by acidaddition, and subsequent extraction of water-soluble polypeptidecomponents) using the materials and procedures as outlined in Examples29 and 30, except that castor meal was replaced by canola meal.

Whole canola meal (Canola Meal MA Viterra 00200, reported to containapproximately 37% protein by weight, obtained from Viterra CanolaProcessing, Ste Agatha, MB) was dispersed in a 1.0% sodium hydroxidesolution, and was then mixed with a 1 M HCl solution to a final pH valueof approximately 4 to 5. The dispersion then was centrifuged and washedwith water (pH approximately 6 to 7) to remove the water solublecomponents (yielding a paste-like slurry comprising approximately 16%solids by weight). The 16% solids slurry, comprising thewater-insoluble/dispersible polypeptide-containing fraction, was used ina subsequent test to disperse PMDI, and then to prepare a particle boardcomposite. The supernatant from the washing step (the water-solublepolypeptide-containing fraction) was collected and retained forcomparative purposes.

In order to assess PMDI dispersability, the 16% solids slurry (thewater-insoluble/water dispersible polypeptide-containing fraction) wasdiluted with pH neutral water to 12% solids. PMDI (containing 1 phrdissolved FeAcAc) then was mixed with the protein-containing dispersionat a weight ratio of 1 part PMDI to 1-part slurry solids on a weightbasis (this mixture is referred to herein as Formula 37-1); this mixturewas proportionally identical to formulation TP12-22-09-8 in Table 48).The PMDI was observed to readily disperse into the water phase of theslurry with no visible sign of PMDI phase separation (within a 2 hourobservation period).

In an analogous experiment, a 12% solids solution comprising the watersoluble polypeptide-containing fraction was similarly mixed with PMDI(containing 1 phr dissolved FeAcAc) at a weight ratio of 1 part PMDI to1-part solids on a weight basis (Formula 37-2). Unlike, the mixture thatwas prepared with the water-insoluble/water dispersiblepolypeptide-containing fraction (Formula 37-1), the mixture comprisingthe water-soluble polypeptide fraction (Formula 37-2) was incapable ofdispersing PMDI, and the mixture was observed to immediately phaseseparate.

Using the procedures as reported in Example 31, a particle boardspecimen comprising 2.59% binder by weight in its dry-cured state wasprepared using Formula 37-1 as the binder (the composition of theresulting particle board composite was proportionally analogous tosample TP12-22-09-8 as reported in Table 49, except that castor meal wasreplaced by canola meal as the source for the water-insoluble/waterdispersible polypeptide-containing fraction). The density of theresulting composite board was measured to be 43.2 lbs/cubic foot. Asample was cut from the composite board and was subjected to boilingwater for two hours (as described in Examples 24 and 30). The sample wasobserved to remain completely intact, even after oven drying.

As noted in prior Examples with other plant-derived products, thehighest degree of moisture resistance and the most efficient degree ofPMDI dispersion is achieved when the Part-B component comprisessubstantially all water-insoluble/water dispersible polypeptidecomponents, or water-insoluble/water dispersible polypeptide-containingcomponents (in other words, the water-insoluble/dispersible polypeptidecomponent may be present together with other water-insoluble componentssuch as cellulosic components that remain when whole meal is used as thestarting material). However, the presence of water-soluble polypeptidecomponents can also be tolerated so long as the dispersability of thePMDI is not adversely affected, and as long as the finished article hassufficient moisture resistance for the end-use application. For example,composites may be prepared with Part-B components comprising mixtures ofwater-insoluble/dispersible polypeptide components with water-solublepolypeptide components at weight ratios ranging from about 30/70 to99/1, recognizing that the lower limit for thewater-insoluble/dispersible polypeptide component will be dictated bydispersion stability, and by end-use performance (e.g., moistureresistance). A more preferred range is from 50/50 to 99/1, and stillmore preferred is 60/40 to 99/1, and most preferred is greater than90/10.

Example 38: Two-Dimensional Proton-Nitrogen NMR Correlation Spectra andCharacterization of a Water-Insoluble/Water Dispersible PolypeptideFraction

The water-insoluble/water dispersible polypeptide fraction from digestedcastor (lot 5-83 as prepared in Example 6) was washed and collected withwater (pH 6 to 7) as reported in Example 20, and was then allowed toair-dry at 23° C. The dried powder was dissolved in d6-DMSO (6.8% byweight) to yield a red homogeneous solution (Sample A). An aliquot ofthe as-made dried digested castor was also dissolved in d6-DMSO (6.8%solids by weight) to yield a comparative homogeneous red solution(Sample B). As noted in previous Examples, solid-state FTIR analyses ofthe same dried powders revealed distinct differences in both the N—Hstretching and carbonyl stretching regions of the solid state FTIRspectra. These spectral differences were attributed to differences inbonding environments for the polypeptide N—H moieties, possiblyresulting from differences in secondary and tertiary structure. One ofthe specific differences involved a shift to lower wavenumbers for theamide-I carbonyl band in the water-insoluble/water dispersible fraction.In order to further characterize these types of differences, atwo-dimensional NMR technique was employed for the purpose ofcharacterizing a very specific subset of bonded atomic nuclei; namely,protons bonded to nitrogens.

The samples were dissolved in DMSO-d6 and were placed into 5 mm NMRtubes. All ¹H NMR spectra were recorded on a Varian INOVA 750 MHzspectrometer equipped with an HCN-PFG (pulsed field gradient) tripleresonance Cryo Probe at 30° C. For one-dimensional (1D) ¹H NMR spectra,a spectral window of 10000 Hz was used with an acquisition time of 3seconds and relaxation delay of 5 seconds. The spectra were signalaveraged for 16 transients using a proton 90° pulse width of 8.6microseconds. The spectral data were zero filled to 132 k points andwere processed with 1 Hz line broadening, then baseline corrected andreferenced to an internal residual solvent DMSO-d6 peak at 2.50 ppmbefore integrating and making plots.

Phase sensitive two-dimensional (2D) ¹H-¹⁵N gradient-HSQC (heteronuclearsingle quantum coherence) data were collected with 2048 acquisitionpoints in the F2 dimension and 768 points in the F1 dimension (90° pulsewidths of 6.3 microseconds, and 33.5 microseconds were used for protonand nitrogen, respectively) 48 transients were collected for eachincrement, with a repetition delay of 1.2 seconds and acquisition timeof 0.124 seconds with GARP decoupling during acquisition. The acquireddata were processed with sine bell weighting and zero filled to8196×8196 points in F2 and F1 dimensions before final transformation toproduce the 2D correlation data.

The results are presented in FIGS. 19-21. FIG. 19 represents thetwo-dimensional HSQC ¹H-¹⁵N NMR spectrum for digested castor lot 5-83 ind6-DMSO. The y-axis represents ¹⁵N chemical shift scale (ppm), and thex-axis represents ¹H chemical shift scale (ppm). The peaks within thespectrum represent protonated nitrogen atoms from all of the fractionsthat were present within the as-made digested castor (i.e., thewater-insoluble/water dispersible polypeptide fractions plus thewater-soluble polypeptide fractions). The multiple peaks in region Bwere observed to disappear upon removal of the water-soluble fractions(see FIG. 20). This indicates that these protonated nitrogens arespecific to the water-soluble polypeptide fractions, whereas the peaksin region A are specific to the water-insoluble/water dispersiblefraction.

FIG. 20 represents the two-dimensional HSQC ¹H-¹⁵N NMR spectrum for thewater-insoluble/dispersible polypeptide extract from digested castor lot5-83 in d6-DMSO. The y-axis represents ¹⁵N chemical shift scale (ppm),and the x-axis represents ¹H chemical shift scale (ppm). The peakswithin the spectrum represent protonated nitrogen atoms from thewater-insoluble/water dispersible polypeptide fraction. The peaks withinRegion B were observed to be very weak in comparison to the analogouspeaks within the digested castor before extraction (see FIG. 19).Conversely, the remaining peaks were predominantly from the protonatednitrogens in Region A. This indicates that these particular protonatednitrogens are specific to the water-insoluble polypeptide fractions. Amagnified view of this region is provided in FIG. 21.

In FIG. 21, the peaks within the spectrum represent protonated nitrogenatoms that are specific to the water-insoluble/water dispersiblepolypeptide fraction. Upon expansion, the two “peaks” appear as narrowclusters that can be readily defined by the ¹⁵N and ¹H chemical shiftboundaries that define them: the ¹⁵N boundaries for both clusters occurat approximately 86.2 ppm and 87.3 ppm; and the ¹H boundaries occur atapproximately 7.14 and 7.29 ppm for the first cluster; and atapproximately 6.66 and 6.81 ppm for the second cluster.

The results of these studies revealed that while the water-solublepolypeptide fraction was composed of multiple types of protonatednitrogen atoms (FIG. 19), the water-insoluble/water dispersible fractioncontained significantly fewer types of protonated nitrogens, and waspredominantly characterized by the presence of two major proton-nitrogencross peak clusters (FIGS. 20 and 21). These differences, like those asseen by solid state FTIR, illustrate that the chemical bondingenvironments within the water-soluble polypeptide fraction aredistinctly different from those that exist within thewater-insoluble/dispersible fraction.

Together, the solid state FTIR and NMR data reveal that the mostpreferred protein fraction for creating adhesives and binders with theunique ability to disperse PMDI (or other oils), and to yield moistureresistant wood composites (or fiber composites) is awater-insoluble/dispersible polypeptide or polypeptide-containingfraction wherein said fraction has a solid-state infrared amide-Iabsorption band between 1620-1632 cm⁻¹; a solid-state infrared amide-IIabsorption band between 1514-1521 cm⁻¹; and a solution-state pair ofprotonated nitrogen clusters as determined by a ¹H-¹⁵N nuclear magneticresonance correlation technique. More specifically, when the pair ofprotonated nitrogen clusters is observed by means of NMR with deuteratedd6-DMSO as the solvent using a two-dimensional HSQC ¹H-¹⁵N NMRtechnique, the clusters are defined by the ¹⁵N and ¹H chemical shiftboundaries that define them: the ¹⁵N boundaries for both clusters occurat approximately 86.2 ppm and 87.3 ppm; and the ¹H boundaries occur atapproximately 7.14 and 7.29 ppm for the first cluster; and atapproximately 6.66 and 6.81 ppm for the second cluster.

INCORPORATION BY REFERENCE

The entire disclosure of each of the patent and scientific documentsreferred to herein is incorporated by reference for all purposes.

EQUIVALENTS

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The foregoingembodiments are therefore to be considered in all respects illustrativerather than limiting on the invention described herein. Scope of theinvention is thus indicated by the appended claims rather than by theforegoing description, and all changes that come within the meaning andrange of equivalency of the claims are intended to be embraced therein.

What is claimed is:
 1. An isolated polypeptide composition comprising aplurality of water insoluble polypeptides derived from castor meal,castor protein isolate, soy meal, soy protein isolate, canola meal,canola protein isolate, or a combination thereof, wherein the isolatedpolypeptide composition is capable of dispersing PMDI in water toproduce a homogeneous dispersion that is stable, by visual inspection,for at least 5 minutes.
 2. The composition of claim 1, wherein thepolypeptide composition comprises one or more of the following features:(i) an amide-I absorption band between about 1620 cm⁻¹ and 1632 cm⁻¹ andan amide-II band between approximately 1514 cm⁻¹ and 1521 cm⁻¹, asdetermined by solid state Fourier Transform Infrared Spectoscopy (FTIR),(ii) a prominent 2° amide N—H stretch absorption band centered at about3272 cm⁻¹, as determined by solid state FTIR, (iii) an average molecularweight of between about 600 and about 2,500 Daltons, and (iv) twoprotonated nitrogen clusters defined by ¹⁵N chemical shift boundaries atabout 86.2 ppm and about 87.3 ppm, and ¹H chemical shift boundaries atabout 7.14 ppm and 7.29 ppm for the first cluster, and ¹H chemical shiftboundaries at about 6.66 ppm and 6.81 ppm for the second cluster, asdetermined by solution state, two-dimensional proton-nitrogen coupledNMR.
 3. The composition of claim 1, wherein the polypeptide compositionis dispersible in water.
 4. The composition of claim 1, wherein thepolypeptide composition is isolated by extraction under neutral or basicconditions, by enzyme digestion, or a combination thereof.
 5. Thecomposition of claim 1, wherein the composition is substantially free ofprimary amines, carboxylic acids, amine salts, and carboxylate salts. 6.The composition of claim 1, wherein the water insoluble polypeptides arederived from castor meal.
 7. The composition of claim 1, wherein thewater insoluble polypeptides are derived from castor protein isolate. 8.The composition of claim 1, wherein the water insoluble polypeptides arederived from soy meal.
 9. The composition of claim 1, wherein the waterinsoluble polypeptides are derived from soy protein isolate.
 10. Thecomposition of claim 1, wherein the water insoluble polypeptides arederived from canola meal.
 11. The composition of claim 1, wherein thewater insoluble polypeptides are derived from canola protein isolate.